Fork the JSON module and remove the usage of B yourself. It seems something easy to do.

JSON uses B to find out when some Perl scalar is a number looking at its internal representation, but this heuristic is very broken because Perl doesn't really differentiate between numbers and strings.

So, you could use a regular expression to check when something is a number of just handle everything as it were a string (no heuristic is going to give you the desired result in all the possible cases anyway).