HoMM3 HD bug reports.

In short, there is no definitive proof, but there is an opinion that a certain structure of neutral unit combat or a part of the Wall of Fire spell has been changed, because now two-hex neutral units periodically attack the Wall of Fire placed very close to them, and not all of them, but only a certain part... This can be seen in a stream; I first noticed this personally in a tournament about 4-5 months ago, and I thought it was a rare bug, but it turns out it's not... It started to repeat, and not just with neutral units, but also in Conquest mode, where nothing like this has ever happened before! And old-school players confirm that they don't remember anything like this.

And Ivan firetosky claims that during a similar episode, a Bone Dragon went berserk against him! But there is no video evidence even for this; please investigate the situation.