Problems opening certain .ogm files

Attempting to open certain (very old) .ogm files in MKVtoolnix GUI results in an error:

However, opening the same files in this 2007-era program (a predecessor to what became MKVcleaver?), I have no issues and am able to extract the tracks and successfully use them with other software (like MKVtoolnix GUI):

https://sites.google.com/site/ogmcleaver/

I have read that anti-virus may interfere, however I have added exclusions to Defender (which also has real-time disabled) and am not seeing any difference. Clearing the cache has no effect, and I confirmed that the versions are the same:

Is there an FAQ entry I missed related to this issue? Or perhaps some way for me to securely share a file sample and/or more detailed debug information to possibly get this error fixed? I was able to use the described workaround, but presumably it would be good to get this fixed anyway.

Cheers!