Sorry for the late reply. Way too much to do.
Signing out from the licensing server is an option. Thanks for the tipp.
It's still more like a workaround. As it means I'll have to play the sign-in, sign-out game a lot. The license doesn't free up automatically. In fact its blocked, even when the machine "using it", is rendering on octane (no traces of corona in those scenes).
Maybe you could integrate a simple "free license" button? Would be small but time-saving implementation :-)