Email variables in SUBMISSION_COMMENT not working (some) (OJS 3.1.2.1)

Dear community,

today, one of our editors has sent an email manually, using the “submission comment” mail-template.
When receiving the mail, some email variables are not properly resolved:

{$name}, {$commentName}, {$comments}

The other two, {$submissionTitle} and {$contextName}, are working just fine.

Should this mail better not be sent manually (because the variables only work when sending automatically)? If this is the case, what action triggers the sending of this mail?

Or should the variable names be changed?

Thank you very much for your help!

Can anyone help with this problem or has had similar experiences? We would be very grateful!