Customer has G450 R016x.00.1.510.1 software. Two MM717 FW0014. About once a day, all phones on one or both digital cards freeze. They look okay, but have no dialtone. Analog board in same gateway still operational. Re-seating the boards resolves the issue. Have moved the boards to new slots, have swapped the boards, nothing resolves the issue. Latest patches have been applied.