Since the upgrade to 5.6.0~rc2+dfsg-1 I have not seen the problem anymore. I suggest to close the bug-report. If it reappears, I will reopen it.
Thanks, Rainer -- Rainer Dorsch http://bokomoko.de/ -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org