Starting RDB$PROFILER.START_SESSION hangs server completely. It stops responding to requests and new connections.

1. To reproduce the problem, run Flamerobin twice and connect to probably any database (but the same database for both instances).
2. In the first Flamerobin instance, go to the system tables, right-click on e.g., RDB$FIELDS, choose "Browse data," and leave the window open.
3. In the second Flamerobin instance, execute the following query (adjust 79 to the connection ID from the first Flamerobin instance).

SELECT RDB$PROFILER.START_SESSION('Profile without "DETAILED_REQUESTS"', NULL, 79)
FROM RDB$DATABASE;

I tried above session on current Firebird 5 snapshot on Windows (5.0.1.1432) 64bit, and the server hung completely.
No new connections were allowed and current connections stopped responding.