This is a follow-on from my earlier mention of troubles with being a Byzantine Rebel. At that time you asked for a sample of the text.

"We counted on you to hold to your promise of support, yet here you cling to Basileus Niketas even as our forces prepare to march. I should have known better than to trust the word of a two-faced brute. Others will know of your duplicity, regardless of the outcome."

That's the dialog I receive after promising my support. I'm hoping you're not about to tell me that's a vanilla bug.

There is nothing like that in any of this mod's localisation files; this is either an issue with the base game or another mod you're running. Sorry.