Bug in Vocal reduction and isolation

See this Forum thread: https://forum.audacityteam.org/t/3-0-0-get-error-when-using-vocal-remove-isolation/60825/6

and this P1 regression bug that was logged as a result
https://bugzilla.audacityteam.org/show_bug.cgi?id=2706
Vocal Reduction and Isolation most options fail

Peter.