I love you for posting, Alex.
I saw your post on the processor thing on another thread and tested it, but it didn't help.
I'm definitely on the latest firmware and driver for the RME, but you are right to call me out for latency Mon. I haven't used it since the rebuild.
But it doesn't happen randomly. I'm running sonar for hours every day despite the problem. It is worst when copying data between projects.
On install, x64 engine was disabled and I had the problem. I now have it enabled and I still have the problem.