Weird walking graphical glitch on Route 2

[doofinc]

Walking on Route 2 after beating Nora at the school. There's a weird glitch where some incomplete sprite is near you when you stop walking. For extra details, in case it matters, I have a Delta Charmeleon walking with me and it's night time. This strange sprite isn't here while walking. Screen size did not matter (started in Large, switched to Normal, still there).

Few more details I noticed: weird sprite is to your top-right when you are facing left, and bottom-right when you are facing down. Walking right only has a flicker of a weird sprite when you stop walking. Walking down has this same flicker issue. Both flicker problems are only occasional. Walking up has no strange sprite.

Found more things. Not restricted to Route 2, but it only started on entry to Route 2. Also, upon restart, it stopped happening.