BTW... it wasn't only ISO to FLAC in foobar that has the 00:00 duration issue as I stated 2 posts back. Even DSF to FLAC has the problem if converted by foobar. It is just that I updated foobar in between those conversions which confused me. Sometimes updating software creates more problems ....
If you're comfortable with the command line, you might want to try using SoX to do the conversion:
https://www.audiofaidate.org/sw/sox-dsd/
It's completely understandable if you'd rather not, though.
You might also try Utilities->Verify Integrity in Foobar.
Weird as it probably sounds, you might also try having Foobar convert your existing FLAC files to new ones. Just use the normal built-in Foobar convert function to convert from FLAC to FLAC and see if the new files behave better.