some mode combinations don't work?

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This bug is easier to notice on the iPad, which likes to keep ones selections in a dropdown instead of replacing them with your next choice (which is what happens on the browser unless you ctr+click)
Salzinnes, mode 8:

mode 6 and 8

mode 6 and responsory (special):

mode 8 and responsory(special): nothing!!

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McGill MS 73 handles 8+ R

CH-Fco2 won't do 8+R or 6+R. Odd...