Its my understanding that a member of your kingdom cannot chief a village owned by another member of your kingdom unless those villages are grey/idle.
I had an instance recently where I chiefed a 1200+ pop city from another player who was idle and their villages were grey. Standard procedure, nothing weird going on so far. I got the village, built up a few things that had been damaged and went to bed.
I woke up the next day and logged on to see that another member of my own kingdom had attacked me with chiefs and the city was now his. It looks like he had been watching this city and waited for someone to chief it, then immediately sent in his army and chiefs to take the village. He was able to do this because the loyalty in the village was at 0 immediately after I chiefed.
If I understand this right, it looks like a member of your own kingdom cannot lower the loyalty of a village in your same kingdom that isn't grey. However, if the loyalty of a village is already zero (for example, immediately after someone else chiefs the village), the loyalty does not need to be lowered any further and the kingdom can still be chiefed by another member of your kingdom.
Is this a bug or am I just going nuts?