Player: V10.12.12
Not sure if I'm the only one getting this, but I've noticed this while using custom floaters/gliders in my levels (the ones that change color to the same as the graphic set's minimap/bridges).
It seems that whenever the lemming uses a glider/floater, the image gets messed up as the lemming floats/glides down. Had to also play some Lemmings Plus levels to confirm if my levels are not the only ones getting this issue. Attached are images of the floater/glider being glitched up (both circled in red).
Ah, I know why this will be happening. I'll put up fixed versions of the Lemmings Plus packs and the custom images for this shortly.
EDIT: Fixed versions for the downloadable addon graphics are now up. Will post in the Lemmings Plus topic when I've updated those.
As a bonus, I also added the recoloring sprites for the Xmas lemming graphics too. :)