Well, that's mysterious.I've kept almost all the localization from the old version of VIET as I intend to reintroduce most of the old flavor events. However, this event isn't one of them - it was something I had in the very early versions of VIET Immersion but removed since it was pretty annoying. Not sure how you'd be able to trigger it either way since I haven't added it back in.
I guess I should comb through the other installed mods to check if someone copied it.
Also, I don't think it's annoying, it's just overpowered.
There's another event after each battle that says something like "we captured a few enemies, what shall we do with them?", and options range from letting them go (+10 Piety) over ransoming them (+gold) to recruiting them (+10 tech, sometimes only military, other times all three). Smaller numbers, but if you have lots of small battles, it sums up. Is that from VIET? If yes, is it possible to add a cooldown or something?