Slight mouse movement lag after attacking

This occurs at seemingly random times when playing original M&B and I have no idea what causes this. I installed TLD and it happened again. After left-clicking during a battle I get a short slowdown with mouse movement (meaning I can't turn myself as quickly as usually during this short moment), making combat more difficult. I'm not sure how I can be more specific, but maybe this has happened to someone else?
I've been searching for answers but have found nothing.

I've had this problem for 2 years now. Massive stuns after and before hitting, sometimes accompanied with missing animations. Some weapons I can't even feint with because it can get so bad. Yet, I run Warband at 120 fps, and have 150mbps download on my internet, with a good ping and no packet loss. I've tried on the lowest graphics, including DX7, single threading, turning off V-Sync (virtually everything in the launcher I've played around with). No idea what on earth is causing this.