With the default settings, when a cron job encounters a syntax error in
the user callback, the error is reported in the system logs, but no mail
is sent to the user.

Thanks for the report.

But I'm sorry I don't understand all details. What does the
user-callbacks have to do with cron?

Maybe the bug is related to cron and not to BIT?

Dear Francesco,

I'm a member of the new upstream maintainer team.

The bug is quit old. Please try to reproduce that problem with the
current upstream version.
If you can reproduce it please open an Issue at upstream and link it
here.

I suggest to close that Debian bug report because it seems not distro
specific.

Kind
Christian Buhtz

Upstream do confirm this bug. Which is related to the fact how Back In
Time reacts on failing user-callback scripts. It seems that BIT doesn't
exit with an error code.

There is an upstream report about it:
https://github.com/bit-team/backintime/issues/1053

Dear Francesco,

can you please have a look at the latest upstream release of Back In
Time. Upstream assumes the problem is solved. Can you confirm this?

Kind
Christian

Upstream has several issues related to error reporting and cron error
mails in context of user-callback script.

I opened a new upstream ticket to reflect this specific bug ticket which
is, to my understanding, about missing cron error mails in case of
syntax errors in the user-callback script.