Conference with choppy audio while other calls are fine


I recently upgraded an asterisk box running asterisk 1.6, DAHDI 2.3 and libpri 1.4.10 to asterisk 11.17, DAHDI and lipri 1.4.15 .

Since then after a while the audio in the conferences become choppy, but all the other calls are fone. The problem seemed to go away after a reboot but a few days later it happened again.

I tested with Meetme of ConfBridge and the problem can be noticed using both, which made me think of a timing problem, but at the same time res_timing_dahdi is in use since the 1.6 version and never had this problem.

Does anyone have any idea of what can be happening?

System data:
CentOS 5.5 32 bits with PAE kernel enabled
Asterisk 1.6 => 11.17
libpri 1.4.10 => 1.4.15