We have FreePBX 2.10 running with a Digium T1/PRI card. Randomly, but most often with calls from cell phones, incoming DTMF tones are not recognized.
If it was a Sangoma card I’d say make sure you turn off the hardware DTMF detection. Not sure if there’s a similar setting for Digium.
After a long hunt, finally resolved incoming DTMF issues on Asterisk 10.10. Customer using 10.10 with Digium PRI card. Symptom: 25% failure on incoming DTMF. Solution: Turn off Fax detect. Once this was turned off, all dtmf issues went away. For some reason, especially on cell phones, system was detecting false fax tones.