#Friendica Server: No access in /tmp warnings

@helpers :
Reviewing the local syslog there are thounds of messages from friendica that read:

Nov 4 13:45:04 localhost Friendica[237585]: worker [WARNING]: Path is not writable {"directory":"/tmp/friendica.mbbit.de","user":"friendica"} - {"file":"System.php","line":556,"function":"isDirectoryUsable","uid":"7d351a"}

Confirmed that the folder

/tmp/friendica.mbbit.de

is owned by www-data:www-data. Seems that PHP tries to acces the files with user "friendica" any idea how to fix that?

BTW: At the moment it does seem to have any negative effect on the site at all.