I see a lot of comments here that are old but I thought I would try my luck with anyone still around.
Whenever war gets declared on me, enemy citystate's city screens don't appear and after clicking on an enemy city, if I click on any other non-enemy city the city screen just doesn't pop up until I reload back into the game. City states also do not show their allegiance during war, so it becomes challenging to distinguish what city states are befriended with who. But then, when I reload back into the game, enemy city state labels look janky, and display an bugged american icon and a bugged spy icon where the name of the city is, and don't go away until peace is made. No idea why any of this is happening. I've tested it in with and without IGE and it seems to be an isolated issue in this mod. Any help? it has a big impact on my game, all advice would be greatly appreciated.

To add:
This week I also learnt that this mod is a part of the Vox Populi community patch which, when I tested, had no problems arose. While I'm sure it has its audience I'm personally not too satisfied with the overhaul it has to the base BNW, so I'm kinda stuck on what I should do next. Thanks.