Perhaps this is intended, at least with Skull Blocks and Soul Jack/Ghoul o' Lanterns, but Suspicious Soul Sand not working with none of these seems a tad wack.

As an extra, though I think this cannot be fixed, soul speed does not work with some non-full blocks such as slabs, soul soil layers or soul candles.

all of these are intentional
Suspicious Soul Sand was made to burn normal fire since it makes them "suspicious"
soul variants of the pumpkins and skull blocks shouldn't technically burn soul fire since it's only a corresponding torch placed inside it