Game crashes/dead player during any melee

[Snowball]

There is a 50-50 chance that my player enters the void when I melee an enemy. I'm still alive, but I float with Sithis and I can't get out of that. I appear to have left combat, but alas as I am indoors usually, I can't fast travel and resort to loading a quicksave. This has been every time I do combat with increased frequency.