The request was formed fine, but I only realized after the fact that the identifier has to be configured for “Apple Music Feed” separately from being configured for “MusicKit”. Once I checked “Apple Music Feed” everything worked fine.

Two other examples worth noting, as I'm trying to determine the best possible path forward. #1 - For Grover Washington Jr's GROVER LIVE album, the parquet files point to two album IDs - 370892329 and 721265199. The first is invalid, while the second is valid. So with that in mind, I thought perhaps whichever ID has a later last_modified_date may be the more appropriate choice. #2 - But then I looked at Branford Marsalis / Joey Calderazzo's SONGS OF MIRTH AND MELANCHOLY album. Here, the parquet files provide four IDs (435851031, 1125447166, 1442978087, and 1443138123). Unfortunately, in this case, the modified dates offer no clue and it turns out the first id and the last id work while the other two do not. Is there any way to determine which links are valid from the data provided within the parquet files?

You are correct - strictly speaking, the documentation matches the payload with an array of strings. Put differently, if Apple only intends to populate this array with one single genre, I'd prefer both the doc and payload to reflect that and avoid the use of arrays where they are unnecessary.