Segfault in ast_bridge_call on unistim when transferring

Asterisk Asterisk Support
1

asterisk 1.8.10.1~dsfg-1ubuntu1 (ubuntu 12.04)
Phones are in unistim. Happens when transferring a call.

stacktrace:

ast_cdr_specialized_reset()
ast_bridge_call()
app_dial.so
pbx_exec()

SegvReason: writing NULL VMA.

Any clues?