So the OSC syntax "/eos/addr/<address>=<level>" is not working as of 3.3.0 (and I think 3.3.3, I can test tomorrow)
The syntax "/eos/addr/<address> <level>" (with a space separating the argument) used to work, but has stopped as of 2.9 I think.
When using the space to separate the argument, the diagnostic tab throws an error.
When using the equals sign, no error is thrown but the level isn't set.
WORKAROUND:
I can get it working with /eos//newcmd/Address/<address>/@/<level>/enter/" but besides it being clunky the online manual says "/eos/addr/<address>" should work.