DTMF problems when call recording enabled


I was running on trixbox for about a year, and lately i upgraded to the freepbx distro.

When i add X or W to the outbound dial command, call recording on demand works fine, but outbound DTMF has problems. ie when i call an office with ivr, it somtimes identifies the wrong key (thinks i pressed 3 when i pressed 5) or dtmf is just ignored.
i tried changing featuredigittimeout to 2000 ms and to 70 ms, made no difference.
both the extension and trunk are using RFC2833.

help is appreciated,