PD flag not appearing for works which are part of a collection (e.g. Song Cycle)

Nov 8, 2019

In the OpenScore Lieder Corpus, it is very common for individual scores (songs) to be part of a song cycle (a single collection listed on imslp.org as Public Domain, containing several different songs).  For example: 
Franz, Robert - 6 Gesänge, Op.6
Holmès, Augusta - 20 Mélodies
Holmès, Augusta - Les Heures

Previously such songs could have a PD flag attached, just by specifying the overall  work (song cycle) as listed on imslp.org.  But recently such songs apparently accept the named song cycle, acknowledged by MuseScore.com as an "Arrangement of a work in the Public Domain" - but the PD flag never appears after the Save action.

I suspect that this happens because the song's title does not exactly match the title of the Song Cycle, and an automated check then removes the carefully-saved PD flag.  
Song Cycle: Franz, Robert - 6 Gesänge, Op.6
Song Title:  Franz, Robert - 6 Gesänge, Op.6, No.6 - Tränen

If you look at these three examples of Song Cycles (Sets on MuseScore.com), you will see one or more songs in each Set without a PD flag.  And these songs have been updated more than once to add their PD flag - but the flag never appears...