https://snipboard.io/jLo1kz.jpg

Was driving to my Iron miner post and looks like wisp time kicked in and didn't like it.

Thanks for reporting.
Looks like bug's been there forever, but unit groups just never happened to become invalid for me or anyone else playing (can't think of how that'd even happen tbh), so it never actually came up. Should be fixed in 0.3.26.

can't think of how that'd even happen tbh

Wonder if it might be some other mod calling .destroy() on a wisp unit group in the same tick, so it doesn't get removed from entities, but invalidated instead.
If that's indeed the case, bit weird that other mod would touch these entities like that - might be by accident and a bug there.
Shouldn't be really breaking anything here now though, can just disband groups of wisps randomly.

HeroTurrets mod maybe? Since "red death" occasionally hits me I turreted out all over the place and that's the only thing that would've takin them out from where I was.
Turret Range Buff mod is the only other thing messing with turrets I think unless Space Exploration or Krastorio2 does.

Anyway, thanks for the fix.