ObjectId undefined value RT-Commandbyemail

Since some days I got a very strange beheavior with RT/RT-CommandbyEmail, the rt-mailgate failed on some tickets (event without Commandbyemail command inside), the procmail told me

RT server error.

The RT server which handled your email did not behave as expected. It
said:

Can’t call method “ObjectId” on an undefined value at /usr/local/share/rt42/plugins/RT-Extension-CommandByMail/lib/RT/Interface/Email/Filter/TakeAction.pm line
79.

Stack:
[/usr/local/share/rt42/plugins/RT-Extension-CommandByMail/lib/RT/Interface/Email/Filter/TakeAction.pm:79]
[/usr/local/lib/perl5/site_perl/RT/Interface/Email.pm:1604]
[/usr/local/lib/perl5/site_perl/RT/Interface/Email.pm:1415]
[/usr/local/share/rt42/html/REST/1.0/NoAuth/mail-gateway:61]

And I’m unable to put this ticket by email back to RT, each time I bounce the mail I got same error.

No update on the server…

Any help would be very welcome.