Fossilize is spamming warnings to my log

When I start Warframe on Steam I see the following lines in my journal log:

Mar 16 16:07:31 debian steam[6391]: Fossilize WARN: Graphics pipeline handle 0x00007f23609a8230 is not registered.                                    
Mar 16 16:07:31 debian steam[6391]: It has either not been recorded, or it failed to be recorded earlier (which is expected if application uses an ext
ension that is not recognized by Fossilize).

This generates an extremely large amount of messages:

$ sudo journalctl --boot=0 --output=cat --grep='Fossilize WARN: Graphics pipeline handle .* is not registered' | wc -l
20085

So much in fact that journal reports that it has suppressed messages:

Mar 16 16:03:16 debian steam[6391]: Fossilize WARN: Graphics pipeline handle 0x00007f23586f0fb0 is not registered.
Mar 16 16:03:16 debian steam[6391]: It has either not been recorded, or it failed to be recorded earlier (which is expected if application uses an extension that is not recognized by Fossilize).
Mar 16 16:03:39 debian systemd-journald[493]: [🡕] Suppressed 11378 messages from user@1000.service
Mar 16 16:03:39 debian steam[6391]: Fossilize WARN: Graphics pipeline handle 0x00007f2368dc6d30 is not registered.
Mar 16 16:03:39 debian steam[6391]: It has either not been recorded, or it failed to be recorded earlier (which is expected if application uses an extension that is not recognized by Fossilize).

Could something be done about this?

I tried using setting the launch options to FOSSILIZE=0 %command% but this didn't stop the messages.

No source file or test is named in the report. Start by reproducing the Fossilize warnings while launching Warframe through Steam and trace where the repeated warning is emitted, then check whether the FOSSILIZE=0 launch option is handled there. Done means the expected unregistered handles no longer flood the journal while relevant behavior remains intact.