We're running into some issues with workflows getting randomly stuck on activities. Frequently this is a simple sdk script that basically just gets a token and creates a token.

Sometimes it's a field assignment activity, sometimes a database query.

When this happens the workflow is permanently stuck. I just found workflows where the last activity recorded was several months ago.

Are there any known issues that would cause this?

Any places to look for what might be happening. I've already gone over the logs, but haven't found anything so far.