I couldn't find this reported elsewhere despite much talk of horde units.

• Description: After attacking and then performing a full move with Hunnic Horde, it could perform a full move again and again the same round
• Steps to Reproduce: 1. Start a battle with Hunnic Horde units // 2. Attack with a Horde // 3. spend its full movement  // 4. It can now spend its full movement (but not attack) again - this can be repeated many times
• Reproducibility: every time I used Hunnic Hordes in 10+ battles (one playthrough on Nation difficulty)
• Expected Behavior: The unit should only be able to perform one full move after attacking as described in the "move and fire" trait.
• Notes: Check if this applies to other units with the "move and fire" trait.

I noticed an AI was also seemingly able to move their Mongol Hordes again and again during battle, meaning I had to wait very long for the battle rounds to end

The hordes seem to have a "move and fire and move and move and move and move..." trait ;)