Create a new node (don't set SortGroup or SortCriteria) with a subset of Now Playing tracks.
Switch to Album Art with Details
Node now has a grouping Alpha on album or album Artist (can't remember)
Somehow the new node gets a grouping (and or SortCriteria) from the subset of tracks.
[Solution]
Set SortGroup and SortCriteria to 0 on new node
Only works until you change the now playing list
[EDITED]
If the now playing is cleared and repopulated the grouping appears on the custom node and only an MM restart will correct it
This is ridiculous EVERY change to the now playing list adds grouping back to the custom node.
[EDITED]
I can't always reproduce it except with the clear now playing list.

