I think I experienced the AI killing its own units while I was attempting to convert them in a campaign scenario from return of Rome.
Might be a programmed tactic. Some people do this because the risk of losing your unit to the enemy is greater than the unit just being deleted sometimes
Although it is fine for humans to do this (but I do wonder without mods is it clearly known by humans which unit in a group is getting converted?), I don’t know that it is that fair for an AI to do this… since they are already doing probably 100 or 1000 things at once. Doesnt seem realistic. Maybe if they only did it for 1 out of every 10 or 30 attempted conversions, sure. But if they do it programmatically at a much higher rate than this, it seems unfair and unrealistic
I can confirm the AI did this to me. Just when I was about to finish converting a heavy cavalry (via Return of Rome), suddenly the AI killed that one unit, which, if I recall correctly, was not within a group but by its own, which would make total sense.
I thirst thought it was a bug having to do with own priests killing themselves in order to successfully convert enemy units/buildings.
I didn’t even know of or think of this tactic I described until a week or two back when I heard T90 mention it briefly during a match in the latest AoE2:DE tournament
PS: Are you sure the AI didn’t have/research the Heresy tech at the monastery? That auto-deletes units and buildings if they are converted. I assume RoR has that tech
No, that technology is not available in Return of Rome. Would be really cool for some civilizations to get it, though, like the Macedonians who don’t have access to temples.