@anamelash I can't remember when it was fixed but it's been at least a year.

In April 2019 when I had the problem, I was on:
Windows 10 Edu (1803) 64-Bit
Opera 58.0.3135.127
WidevineCDM 4.10.1196.0

Now in November 2020, I'm on:
Windows 10 Edu (1909) 64-Bit (unable to receive 2004 and 20H2 updates yet)
Opera 72.0.3815.207
WidevineCDM 4.10.1610.0