Heroes 3 glitch: My hero got duplicated

[LoDebar]

I was playing my custom XL SOD map I made 1½ years ago, recruiting heroes for every captured town in the hopes of getting a high-level hero that formerly belonged to another team. Suddenly I noticed Rissa was recruitable... but I already had her in another town.
She had some troops with her, in fact the exact troops that the original Rissa had. So I noticed because I put the dupe's troops on another hero then dismissed her.

Then it got weird.

A while later, the last enemy had recruited the fake Rissa and was chasing down one of the unguarded towns. I could've fought her with my main hero maybe, but I instead took my original Rissa out of her town and had her run about the map. This caused the fake to disappear. But then after I was done with my turn, the enemy was controlling MY Rissa and moving her about. I didn't like this, so next turn I dismissed her. I made my moves, ended the turn, and then the game crashed.

Anybody see this before? Or better yet, know what caused it and how to prevent it?

[Bandobras Took]

I've had it happen during SoD campaign maps, where Gem or Gelu ended up being hireable as a level one hero when they shouldn't be, but I'm not sure what caused it.

[Korbac]

I recall that happened to me before and it crashed the game. It's just a very rare bug I guess.

[Bersaglio]

That's... weird. Which game version are you using? I believe that in the original H3: SoD (v3.0 or patched v3.1/v3.2) it is impossible to see such bugs unlike H3 Complete (v4.0) especially with some kind of unofficial modifications/hacked game exe (with Safedisc removed)/etc.

[Pol]

Not so rare in the past. It could happen often before the patches. Usually invoked when conquering the town, doesn't matter if neutral or owned. The hero may duplicate. And it still can happen but veeery rarely.

Symptoms:
After conquering the town the same hero is in the garrison and as a visiting hero. Next turn both heroes have different owners and same army.

Resolution:
Load the game before the event occurred.