6th Gen Nature change glitch in Pokemon X?

[LuminaryOrphan3]

So I put a Froakie with Protean I got from Wonder Trade randomly in the daycare with a ditto to give another one to my friend. It was there until it reached level 21 (it started as level 1). I know for a fact that it used to have a Modest Nature, but when I took it out, it had a Timid Nature! I know it had a Modest Nature because I remember that that was the nature I wanted for it (it was a lucky trade for me). Has something similar to this happened to anyone else?

 

[Magikarp From Hell]

Are you a 100% sure? Because I've done some searching and I didn't find any simmilar cases.

 

[Whitney's Shaymin]

Are you 100% sure you're not mistaken?

That's a little inappropriate... As for the topic, timid is another nature made for froakie so I think you just maybe had a brain fart or are lying...