Player: V10.13.16:788B9C0
If a level has a skill that is set to infinity, and you assign that infinite skill to a lemming, the infinite loop symbol will turn into the number "99" and count down every time that skill is used.
Confirmed that I can reproduce this bug. Will investigate why it's happening (and come up with a fix) when I have a chance.
Fixed this for the next update. This bug might also be present in the later V10.12.XX releases too (haven't tested, but the change that caused this bug to occur was made quite some time ago and probably just went unnoticed as infinite skill count is not frequently used).