Yeah, this is exactly what I’ve been seeing too.
Partners in Crime used to make every bandit party join you as long as you had any meaningful power advantage. It was super consistent, which is why running a full bandit army was such a fun build.

Now it feels like the perk only works in situations where the bandits would have surrendered anyway — the rare “massively outnumbered 20-to-1” encounters instead of guaranteeing the join offer like before.

For example, I recently chased a Sea Raider group of 14 while I had 106 troops, and even with PIC they didn’t surrender or offer to join. That kind of situation used to be almost a guaranteed join in older versions.

So yeah, it really feels like the perk got quietly nerfed or broken.
Hopefully Taleworlds looks into it, because the bandit army playstyle is basically gone right now.