Problem sorting by composer last name

In Roon 1.5 (323) I am having a problem sorting the Tracks view by composer last name.

I attached two screen shots. In the first, composer sorting is set to first name, the screen shot shows the first page of the Tracks view, the sorting in this page and in all subsequent pages appears OK.

In the second screen shot composer sorting is set to last name. The first Tracks view page shows the composer “Andrew McIntosh” at the head of the list. This is not correct, so far I cannot figure out why this composer appears first. Also, subsequent Tracks view pages appear to me in a somewhat scrambled order.

Note that in this library, all albums are unidentified and also the multi-part composition grouping option is disabled. For this library I prefer the use of file tags exclusively. Also for this library I prefer no composition grouping in the Albums views. Maybe this library setup is relevant to this sorting problem?


Composer first name sorting:

Composer last name sorting: