Hey man
I HAve to agree, I have suffered all of these things to the point I no longer use Rig Manager.
I stopped using RM about a month ago when I copied 10 performances from slot 1-10 to slot 20- 30 as I wanted to change all amps to a new pack for testing in the studio. I was more than annoyed when it deleted performance 1 and 20 (the entire lines). I had created a backup so restored the Kemper via Rig Manager to find the performance was not there so had to rebuild the entire song from scratch.
I think most of the issues come from Rig Manager losing connectivity to the Kemper as this happens a lot. I will start to use RM, everything is fine, then suddenly I start to save (new performance, slot order, different amp) and RM does not reflect what's on the Kemper. I always have to restart RM, I have tested this with multiple USB cables, multiple revisions of RM, usb3, usb2, USB passive and active hub and also multiple computers.
I just came to the conclusion that the Kemper is fantastic, I mean out of this world, but the software development or the USB implementation is not quite up to scratch (be that RM or the USB)
For the record this is only in performance mode, auditioning amps is never a problem.
As an aside it has really taught me to understand the Kemper interface from the screen and I must say I have very little use for RM apart from auditioning.
Hope you find a resolution
Mike