Unintentional footprints?

I’m so confused by this that I don’t even know which category I should put this in.

I have a little AI-controlled beast running around the default first person map. All it does is go to a random location, nothing too complicated.

But it looks like it’s leaving “footprints” every now and then. I know it’s not supposed to be there because (a) I haven’t programmed footprints in the game, and (b) they appear randomly as it runs around the map.

What are they? And is there something I can do to make sure they don’t show up? I do want to implement footprints eventually, and these things (whatever they are) will probably mess up the appearance.

See this, maybe

yup, switching from VSM to normal shadow maps worked for me. thanks!