There's an approximate timer for Castrum. Best thing to do is not do any critical engagements when the time gets close. I usually join a castrum prep group and we'll do skirmishes/VEs for a while, but once we get to about the 10-15 min mark, we stop with the CEs.

It's still leagues better than BA queuing was.

They probably don't want to have it be a DF thing because the people would stop doing Bozja altogether and would just sit in queue.