[Error] "Phantom" sprites after end credits

[StCooler]

Hello;

So, I encountered this bug when testing the end credits (yeah, I finally reached that point). I am using Essentials v18.1.
So basically, after I run the end credits, I have a bug where some sprites remain on the screen even when I'm moving.
Here is a video of the bug:



So basically I am on map A, I click on an Event; the event darkens the screen and then teleports me to map B:

Spoiler:

On map B, the Event is an autorun, it plays the end credits, displays some text, and then brightens the screen.

Spoiler:

And voilà: some sprites are like "stuck" to the screen.

A few more details:
In the Autorun event, I have three lines:

$scene = Scene_Credits.new
$scene.main
$scene.createSpritesets

while in the Docs, they say we only need the first line. Actually if I do this, the credits don't play.
So I added the second line, which actually plays the credits.
But if I do, I have countless bugs about some spriteset attributes being "nil" when trying to display some text, so I figured I would need to force to create the spritesets, hence the third line.

Also, here is the full code for those end credits. I haven't changed anything:

Spoiler:

# Backgrounds to show in credits. Found in Graphics/Titles/ folder
CreditsBackgroundList = ["credits1","credits2","credits3","credits4","credits5"]
CreditsMusic          = "Credits"
CreditsScrollSpeed    = 3
CreditsFrequency      = 9   # Number of seconds per credits slide
CREDITS_OUTLINE       = Color.new(0,0,128, 255)
CREDITS_SHADOW        = Color.new(0,0,0, 100)
CREDITS_FILL          = Color.new(255,255,255, 255)

#==============================================================================
# * Scene_Credits
#------------------------------------------------------------------------------
# Scrolls the credits you make below. Original Author unknown.
#
## Edited by MiDas Mike so it doesn't play over the Title, but runs by calling
# the following:
#    $scene = Scene_Credits.new
#
## New Edit 3/6/2007 11:14 PM by AvatarMonkeyKirby.
# Ok, what I've done is changed the part of the script that was supposed to make
# the credits automatically end so that way they actually end! Yes, they will
# actually end when the credits are finished! So, that will make the people you
# should give credit to now is: Unknown, MiDas Mike, and AvatarMonkeyKirby.
#                                             -sincerly yours,
#                                               Your Beloved
# Oh yea, and I also added a line of code that fades out the BGM so it fades
# sooner and smoother.
#
## New Edit 24/1/2012 by Maruno.
# Added the ability to split a line into two halves with <s>, with each half
# aligned towards the centre. Please also credit me if used.
#
## New Edit 22/2/2012 by Maruno.
# Credits now scroll properly when played with a zoom factor of 0.5. Music can
# now be defined. Credits can't be skipped during their first play.
#
## New Edit 25/3/2020 by Maruno.
# Scroll speed is now independent of frame rate. Now supports non-integer values
# for CreditsScrollSpeed.
#
## New Edit 21/8/2020 by Marin.
# Now automatically inserts the credits from the plugins that have been
# registered through the PluginManager module.
#==============================================================================

class Scene_Credits

# This next piece of code is the credits.
#Start Editing
CREDIT=<<_END_

Pokémon Bugged Sprites
by StCooler

_END_
#Stop Editing

  def main
#-------------------------------
# Animated Background Setup
#-------------------------------
    @sprite = IconSprite.new(0,0)
    @backgroundList = CreditsBackgroundList
    @frameCounter = 0
    # Number of game frames per background frame
    @framesPerBackground = CreditsFrequency * Graphics.frame_rate
    @sprite.setBitmap("Graphics/Titles/"+@backgroundList[0])
#------------------
# Credits text Setup
#------------------
    plugin_credits = ""
    PluginManager.plugins.each do |plugin|
      pcred = PluginManager.credits(plugin)
      plugin_credits << "\"#{plugin}\" version #{PluginManager.version(plugin)}\n"
      if pcred.size >= 5
        plugin_credits << pcred[0] + "\n"
        i = 1
        until i >= pcred.size
          plugin_credits << pcred[i] + "<s>" + (pcred[i + 1] || "") + "\n"
          i += 2
        end
      else
        pcred.each do |name|
          plugin_credits << name + "\n"
        end
      end
      plugin_credits << "\n"
    end
    CREDIT.gsub!(/\{INSERTS_PLUGIN_CREDITS_DO_NOT_REMOVE\}/, plugin_credits)
    credit_lines = CREDIT.split(/\n/)
    credit_bitmap = Bitmap.new(Graphics.width,32 * credit_lines.size)
    credit_lines.each_index do |i|
      line = credit_lines[i]
      line = line.split("<s>")
      # LINE ADDED: If you use in your own game, you should remove this line
      pbSetSystemFont(credit_bitmap) # <--- This line was added
      xpos = 0
      align = 1 # Centre align
      linewidth = Graphics.width
      for j in 0...line.length
        if line.length>1
          xpos = (j==0) ? 0 : 20 + Graphics.width/2
          align = (j==0) ? 2 : 0 # Right align : left align
          linewidth = Graphics.width/2 - 20
        end
        credit_bitmap.font.color = CREDITS_SHADOW
        credit_bitmap.draw_text(xpos,i * 32 + 8,linewidth,32,line[j],align)
        credit_bitmap.font.color = CREDITS_OUTLINE
        credit_bitmap.draw_text(xpos + 2,i * 32 - 2,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos,i * 32 - 2,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos - 2,i * 32 - 2,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos + 2,i * 32,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos - 2,i * 32,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos + 2,i * 32 + 2,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos,i * 32 + 2,linewidth,32,line[j],align)
        credit_bitmap.draw_text(xpos - 2,i * 32 + 2,linewidth,32,line[j],align)
        credit_bitmap.font.color = CREDITS_FILL
        credit_bitmap.draw_text(xpos,i * 32,linewidth,32,line[j],align)
      end
    end
    @trim = Graphics.height/10
    @realOY = -(Graphics.height-@trim)   # -430
    @oyChangePerFrame = CreditsScrollSpeed*20.0/Graphics.frame_rate
    @credit_sprite = Sprite.new(Viewport.new(0,@trim,Graphics.width,Graphics.height-(@trim*2)))
    @credit_sprite.bitmap = credit_bitmap
    @credit_sprite.z      = 9998
    @credit_sprite.oy     = @realOY
    @bg_index = 0
    @zoom_adjustment = 1.0/$ResizeFactor
    @last_flag = false
#--------
# Setup
#--------
    # Stops all audio but background music
    previousBGM = $game_system.getPlayingBGM
    pbMEStop
    pbBGSStop
    pbSEStop
    pbBGMFade(2.0)
    pbBGMPlay(CreditsMusic)
    Graphics.transition(20)
    loop do
      Graphics.update
      Input.update
      update
      break if $scene != self
    end
    Graphics.freeze
    @sprite.dispose
    @credit_sprite.dispose
    $PokemonGlobal.creditsPlayed = true
    pbBGMPlay(previousBGM)
  end

  # Check if the credits should be cancelled
  def cancel?
    if Input.trigger?(Input::C) && $PokemonGlobal.creditsPlayed
      $scene = Scene_Map.new
      pbBGMFade(1.0)
      return true
    end
    return false
  end

  # Checks if credits bitmap has reached its ending point
  def last?
    if @realOY > @credit_sprite.bitmap.height + @trim
      $scene = ($game_map) ? Scene_Map.new : nil
      pbBGMFade(2.0)
      return true
    end
    return false
  end

  def update
    @frameCounter += 1
    # Go to next slide
    if @frameCounter >= @framesPerBackground
      @frameCounter -= @framesPerBackground
      @bg_index += 1
      @bg_index = 0 if @bg_index >= @backgroundList.length
      @sprite.setBitmap("Graphics/Titles/"+@backgroundList[@bg_index])
    end
    return if cancel?
    return if last?
    @realOY += @oyChangePerFrame
    @credit_sprite.oy = @realOY
  end
end

Has anyone any idea why this happens and/or how to solve this?
Thanks in advance.