In band dialling problem

I have just upgraded to to FreePBX 12.0.39 and I now find that when accessing voicemail and conferencing systems where you are required to enter “#” to terminate a command like password, the PBX responds with “Transfer?” and waits for further input. It seems the “#” key is intercepted and not passed on the the VM or conferencing system which did not occur prior to upgrade. How can I stop this happening?