This seems to be a paradox when running a perl script from a session then executing perl again on the same session from a different thread.
I fixed it by converting any execution of perl in the execute_on_* family of operators to only run background mode which is to store the command in the session stack to be executed only by the session thread instead of on the spot by the outide thread.  changing the execute_on_answer to perl::/path/to/script.pl would also eliminate the crash in code that has not been updated with this patch.

This is just a limitation of embedded perl we have to live with.