Sander, I had the exact same issue if you recall some emails I sent to you. I never had any of those issues with the spektrum receiver, only when I switched to the ezuhf rx did I get the issue.
Now it was fixed with me switching to cc Phoenix 35's.
I never did use the BEC on either of the ESC's on my twinstar, but used the CC BEC from the beginning.
Somehow it seems that ezUHF and some ESC don't work correctly.
I suggest removing props before further testing though.