yes normal kerfus is SUPER buggy in time lapse, he needs tweaks for sure so make sure you turn him off first. They should show up on radar still if you want to try to track them down (you might need to take down all your cameras and throw the atv across the river and such around base as they also show up, if you're sure he's not near base he may have somehow gotten outside the fence, in which case IMO not super worth tracking down), and there is also a >>>>> SPOILER/SECRET >>>>> place to clip through the floor of the base on the porch near the workspace window, he may be stuck under there.
If you do find him stuck somewhere and can't free him/fish him out, drag a workbench over and disassemble/reassemble him