I don't have a premium account so I can't actually confirm this is the case, but I had one of those "wait, a sec...." moments while making brekfeast this AM.

As of right now, each sensor entity does NOT check it's workspace ID with the current time entry workspace ID.
This means that if you have multiple work spaces, you'll have multiple sensors and EACH SENSOR will have the name/description of the current time entry as it's state ... even if the time entry belongs to a workspace OTHER than the one assigned to the sensor.

The intended behavior is that only ONE sensor per account will have a non-None state at one time. This is because Toggl only allows ONE time entry per account, regardless of the number of workspaces.