Stop managed databases with "proshut dbname -by" instead of "dbman -stop -db dbname". Open PROMON / PROSHUT sessions will be terminated as part of the shutdown process.
Upgrade to OpenEdge 11.5 where PROMON sessions can be disconnected. For further information on disconnecting running PROMON sessions refer to Article:
If the database has been shutdown with DBMAN -stop (or through the OEE Console) while PROMON session(s) are still active:
1. QUIT all interactive PROMON or PROSHUT screens.
2. Stop PROMON batch scripts from running.