This is just an educated guess, but it could be an issue with the on-disk record formats. A quick look here: https://www.sqlite.org/fileformat2.html shows that variable length types like BLOB and TEXT are denoted by a type code value greater than 12 that is even or odd (respectively). The only wiggle room looks like values 10 and 11, but of course there would have to be some completely separate way of denoting the size.