Of late I have noted that Picard scan is not producing/fetching AcousticID for tracks less than (it seems) 2 minutes in length.

Picard gives the following error in debug log:

E: 21:05:39 Fingerprint calculator failed exit code = 2, exit status = 0, error = Unknown error

An example of a release that I have had problems with:
https://musicbrainz.org/release/d5515e40-fefe-4023-8c4f-2ef9b0302182?tport=8000