Just gave it a try, even a newly created encrypted DB under Catalina is being unmounted automatically. This time after 5min without use.
Actually it corrupts my DB, since files are being imported while the DB is being unmounted. Afterwards files are either not located in the DB (but can be found as orphaned files) or are blank pages!
Anyone a hint how to fix that?
Right now I return to an unencrypted DB, since my document management is to important to use a unreliable technology!