This is not a question, I simply could not find bug reporting thread, so writing it here. I've compiled most recent MaNGOS Two 0.21 at Ubuntu 19.04 with MySQL, everything passed just fine.
Got complete client 3.3.5a (12340) from some site, checked it for completeness - works good, Vanilla, BK, WoTL all available at that site. Extracted dbc, maps, vmaps, mmaps with no errors at all, set realmd and mangosd to start as daemons (as recommended by Talendrys - my personal thanks for perfect installation guide). Just had to correct priorities in mangosd.conf - LogLevel from 3 to 0 and LogFilelevel from 0 to 1 to avoid endless events loop in mangosd console when starting it manually.
Well, mangosd shows lots of database mistakes when starting - incorrect spell targets, incorrect paths for monsters - but all these are non-ctitilal, it starts well.
Then, when checking playability. I've found that predefined characters aren't able to go to BK and WoTLK areas, run within the Classic content only. Client says something kinda 'You must have BK/WoTLK expansion to be installed to go here or there'. Config.wtf says - SET accounttype "CL". Changing to "BK" or "LK" doesn't work indeed, it respawns at every client start. Checked mangosd.conf variable Expansion - it is set to 2 by default, it's okay.
It took me a while to find that default accounts at MaNGOS Two 0.21 are set to use no expansion: column 'expansion' at table realm.account shows all zeroes.
Why don't to correct this small omittance? Also it would be good to put LogLevel=0 and LogFileLevel=1 values into mangosd.conf (if it also fits for other systems than Linux).