I only assume that prime 3 spidertron should be targeted by enemies. If this the case than in my game they are not targeted at all. I can just walk through the enemy base without any aggro at all. (I also have arachnids and armoured biters installed)

Furthermore, I was unable to damage entities belonging to other forces than 'enemy'. I only experienced this in one of my WIP mods similar to Enemy Race Manager. Maybe this strange behaviour can also be experienced with ERM.

Ah, you're right. I tried marking the spiders as military targets, and now they are targeted by the biters when using the remote. Thanks for the report! Will put this for in the next release.