My default workflow is make a decrypted backup of the disc, then open the backup and create .mkv files from there. I often see speeds in that range when creating .mkv files from the backup.
I've been lazy and am still on 1.17.6 so I can't confirm the OP's observations. However, I've seen other comments to the same effect on the forums.
I've seen other comments to the same effect on the forums.
Yeh I think I've seen 3 different bugs for 17.8/9 reported on here. Also dtech's thread viewtopic.php?f=3&t=33061 could be an oversight/missed opportunity that could be remedied. Regardless, it might be code maintenance time.