I am running into the same problem.
I am using macOS 13.4.1 and RigManager 3.4.43.
Kemper and Mac are connected via a USB hub.
When I unplug and plug the USB-B side of the Kemper, I can connect from RigManager.
The output result of the system_profiler SPUSBDataType command before and after unplugging and plugging the USB device is that the "Location ID:" in the Profiler has changed.
Before unplugging, Location ID: 0x08332100 / 17
After plugging in, Location ID: 0x08332100 / 18
Hopefully this will be resolved in the next version.