Windows getting 'pinned' across spaces

Running OSX 10.13.6, TotalSpaces2 v2.6.24.

I’m in the process of swapping over my MacBook Pro. Same OS / version of TotalSpaces. The old Mac’s TotalSpaces worked flawlessly. On the new Mac I’m getting windows frequently, but intermittently ‘pinned’ across spaces. So swapping spaces leaves a window on screen across spaces, as well as adding the new spaces windows (which can be in front of, or behind the ‘pinned’ windows. As far as I can see, the settings match between the comps.

It may be only happening with multiple monitors. I think I remember it happening without additional monitors, but I could be mistaken…

Any suggestions of what I could try?

This hadn’t appeared for a while, and then came back. Looks like it’s related to rebooting without an external monitor and then swapping to use external monitors. This doesn’t happen with my other comp. I have no idea what the difference could be…