No messages in MUC after OF update

Hi,

updated from OF 4.2.3 > 4.4.1
updated Monitoring Plugin from 1.7 > 1.8
using embedded DB
having 6 Rooms, archiving enabled for every room, keep messages forever

after update, 1 room is empty (no messages shown), some (older)Messages are missing in other rooms.

experienced this the last time while upgrading as well

tried to rebuild the Index -> no change.
But i see the messages in archive

can someone provide help? Thanks ind advance!