A puzzling palm leaf (updated)

[Dan Lusthaus]

>how such a sheet might have been
> kept with the manuscript since it is not fitted with holes for binding.

Jacob,
Without a detailed and verifiable history of provenance, that would be 
impossible to answer -- one can spin out infinite speculations. For 
instance, at some point the ms. was owned by, or in the same room as a 
scribe or scribes to be, and one of their practice sheets got shuffled in. 
Maybe the son of the ms. owner was doing his homework by using the aksaras 
in the ms. as his exemplars. How did the practice sheet get shuffled into 
the ms? Unintentionally, perhaps.

Many alternate scenarios can be imagined.

cheers,
Dan