Ability to runsprint occassionally doesn't work

Occasionally the ability to run (shift) or toggle run (CAPSlock) doesn't work at all. The game does say I'm over encumbered but usually I'm at 180/215 weight. Keep in my mind, I am using FCOM superpack with texture packs, but no other mods in exception to Midas Magic. I'm not sure if it is being caused Combat Fumbling which I have deactivated in-game as an attempt to fix this running issue. It happens especially whenever I just got killed and have to load the latest save in which I find myself unable to run.
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