Yeah this isn't specific to Warlord, or this particular situation, it's just how the AI behaves in the new Beta 14 for now, as a side effect of having blocked the earlier jumping abilities that people always complained about. Not easy to have everything
If you help the front line clear out the enemies ahead, and/or simply move further from the fight, they will advance normally, but if you're close by they are going to be more reserved, or even remain stationary until there's enough free room / no hostiles blocking the way. Too many bots in that small area.
I'm still waiting for someone to provide me with a save file that demonstrates a behavior like this
without being obviously blocked by a ton of allies, like Hermelin was recently showing on Discord, because that will be a more fundamental issue to resolve--directly doing anything about this case is probably not that helpful by comparison, since it's behaving as intended for now. What you can also do, if you don't want to advance, is intentionally move into their midst to swap them around a bit, which frees them up.
This will likely be adjusted for Beta 15, once I have the right data.
Edit: Actually I've gone ahead and made mutual allies able to more freely swap now under a greater variety of conditions. Was thinking about doing this last week but since it wouldn't address the specific issue Hermelin showed with just a couple sparse bots I had wanted to wait on it, though I think this will probably be needed anyway, now that they're not so free to jump.