I don't know if it can have something to do with any other mods (I have lots, but not particularly game changing), but after some time I keep finding my spiders far in the wilderness on different planets. The only exception so far seem to be Fulgora (coincidence?) and Aquilo (obvious reasons, yet they try to pathfind into water)

I have some pics but it's exactly what I said: They started in my factory and now some are on the edge of charted territory.

Thank you for the report- that is not intended. I will look into it, there is probably something I overlooked in the list of entities they’re allowed to find and go to.

I did some testing on the save after disabling all mods besides this and it still seem to work like that. I also tried it with and without Spidertron Enhancements but it doesn't seem to matter. Two spiders on Vulcanus died to a demolisher and some of the Gleba ones wandered into the pentapod nests outside the range of my legendary artillery. Fulgora still seems oddly fine. Maybe they just don't path onto the oil. Also the one on Aquillo gets stuck between two islands. It even tried to get into the ocean one time, but that was before I disabled other mods. I don't think it's just some missing entity, looks like they ignore the filter whatsoever. I haven't used the mod before so I'm not sure if something broke it, maybe the mod just don't work on the recent 2.0.63 patch.

So, I wasn't able to directly reproduce this behavior, but I think I know what may have been causing it and reworked some of the logic that controls what happens when they get stuck or can't find a valid target to wander to.
I think what was happening was that they were failing to find wander targets, which caused them to move a couple tiles over and try again. But when searching for a new position to move over to, only water tiles were ignored, causing them to attempt to go onto other impassable terrain (overlooked during migration of mod to 2.0 - oops). I've changed that so now they shouldn't get nudged onto any tiles that the player collides with.
I really hope this resolves this issue - please let me know if it helps, or if your spiders are still acting up. I do not want the spiders to get damaged at all because of this mod, and I appreciate the report and your time looking into this.