maybe related to the upgrade to Debian buster on that machine:
Mär 17 04:21:08 backup amdump[9101]: File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob() instead. at /usr/lib/x86_64-linux-gnu/amanda/perl/Amanda/Amdump.pm line 330. Any perl coders reading?
