Editing posts with BlogJet – missing categories

I still use WP 1.2 (upgrading asap) and the latest BlogJet 1.2 Beta.
While posting a new entry with even several categories works like a charm, the download of a single post for editing (history feature) does not include multiple categories (if selected). See https://blogjet.com/cgi-bin/yabb/YaBB.pl?board=bugreports;action=display;num=1100912521 for more information in depth.
Does any of the developers have a clue how to resolve this burning issue?
Thanks in advance for any support in this respect.