A streamer that I watch had this (or a very similar) issue last week. He's in Act 3 and was only able to jump around for a while. He was out of combat. He seems to have fixed it by removing pieces of his gear (specifically his armour) and putting them back on. After doing that, he was able to move around fine for the rest of the session. He even had to reload to that broken point and do it again. It was consistent for him. Hopefully it helps you or someone else with the issue.
For additional context, it happened to him after throwing a piece of armour at a secret door with hopes of breaking it. The armour sort of glitched out and he picked it back up at the base of the door. Then he was unable to move except by jumping.
