Tabs Refuse to Be Moved

[LookingForWayOut]

Not sure if this is the same issue as #119.
This has gone on for months on both FF 40+ and, as I recently copied over, FF ESR 52.3 (64b). Issue on multiple computers as well running other versions of FF and Windows (using the W7 I am on now as an example).
With TK2 2.3.1, my tabs are set to be placed by opener but issue happens even if I turn that off.
What happens is now and then a group of tabs, that have been nicely inactive for a long while on the bottom of the tab list, will decide to move up to the top of the list. On their own. Then when i try to move them down, or other tabs up, the tab I am moving goes back into the spot it is in.
I then have to ungroup all tabs and turn back on, via options, to group by opener. Then it seems to work for awhile until it does it all over again.
Anyone encounter this?