I have the same issue. It's been happening since I updated to 1.5.41 on Mac OS X 10.11.4. The quick fix is unplugging the USB from the Mac and moving it to a new port. If you unplug the USB from the current port and plug it in to the same port, doesn't work. As soon as you move it to a new port, my profiler appears in the rig manager. I tried restarting the computer and that worked once. I tend to just put the computer to sleep and turn off the Kemper.
In earlier versions, as soon as the Kemper would boot up, it'd show in the Rig Manager. I've had to, for quite some time (not sure which version caused the change) launch the Kemper and then quit out the Rig Manager and relaunch if I'm just waking my computer from sleep.