Weird Pokemon Crystal Bug

[Atomic_Aegis45]

I found a weird bug on Pokemon Crystal. Pokemon in my boxes are having their sprites swapped for other Pokemon, even ones I don't have anymore like Cyndaquil swapping with Sandshrew after Cyndaquil evolved. Is there a way to fix it? This may not be the right place to ask this, I have never used the site to ask questions before I just really need help and have no idea how to fix this.