Is quire 10 a single bifolio, or two folios stitched together?

[Jorge_Stolfi]

When the 2016 Yale photo facsimilar was produced, the manuscript layout was double-checked before producing the figure on page 24, which is equivalent to the diagram on my web site, so this is definitely a single sheet / bifolio.

Thanks!... But then what is the explanation for the gap that we see in the BL 2014 image of f69v+f70r1+f70r2?
   
(My guess was that f69  and f70 behave like a single bifolio (as per the foliation diagram), but are in fact two separate pieces of vellum stitched together.  This stitching would not be part of the book binding, but would be prior to and independent from it.)

(Or perhaps the parchment was brittle and the bifolio split from too much handling, and was mended at some point by an owner or librarian.)

All the best, --jorge