[Jeffrocchio@gmail.com]

I just noticed today that the 'Artist' (Artists) metadata field isn't importing as a list. Instead it is importing as a single, comma separated, string. I could be crazy (in fact some say I definitely am) but I swear this was importing as a list in the past (and the PDFs I imported during my forScore migration, for which I had populated that field, are showing that field as lists in MobileSheets).

I just now tried setting the Artist metadata field in a test PDF using: 
comma [space], 
semi-colon [space], 
comma [no-space], 
semi-colon [no-space]

None of those four tested formats worked to get a list vs single string.