Unity Call handler DTMF issue

It was around Halloween time. I was building one call handler for each local site. We start getting ticket saying unity Caller option "0" ring on caller input "2".Hmm. Really!! Who cares, it must be user error. Unfortunately, more ticket started to come. This is alarming for sure. Now it's the time get to the bottom of this. Lets' dig in.

I build another call handler. See if I can replicate the same issue. After making around 8-9 call. It is happening. What the hell is going on here?
Hmm, Opened a ticket with Cisco. We did some capture on ISR4321. but we're not able to see what DTMF code we were receiving on CUBE. Then Cisco said this model does not show DTMF. SO we did capture on cube network port.

Long story short......It was AT&T was sending us wrong DTMF.

At&T "After referring this issue to our Sonus TSM support, they did some maintenance to refresh DSP cards the customers failed calls went over. Please have the customer retry these calls to ensure their DTMF issue is now resolved."

 Good Day.