Has anybody run into this problem before? My dad's phone can dial a number with a 2 in it, but once he's connected and tries to enter a code to join a conference call, the 2 won't depress. All the other numbers work properly. FWIW, here's the software info:

Hardware version 0003
Software vers 1.22.651.3 71ORD
Network Sprint
Mobile Network Type LTE

Model # EVO MEID 99000065733638
Software Android version 4.0.3
HTC Sense Vers: 4.0
HTC SDK API level: 4.20

Kernel ver: 3.0.8-01368-g6fdcee1
Baseband Vers: 1.05.11.0606
Build #: 1.22.651.3 CL78702 release-keys