Should be pretty easy to fix in ChangeSubject.vm. I'm testing it locally then will submit to gerrit for review.

If it works, I'll submit the fix upstream as well. Thanks for reporting this.

Submitted for us in gerrit change 13325.

Also submitted upstream.

Chad's reverted upstream change: https://gerrit-review.googlesource.com/#/c/36540/

Upstream revert comment: "The truncation failed when the subject length was 59, throwing StringIndexOutOfBoundsException and causing email formatting to abort with no message sent."

Curious if same problem happens in our applied downstream patch (Gerrit change #13325)?

I had reverted our custom patch out of caution.

New fix was accepted upstream in commit 9fe238ec19d1ef5b16193b524e9b07cd031de46b
https://gerrit-review.googlesource.com/42424

Submitted downstream patch for us in 05ae70be072d95721572ceeb5d2a92751f5a81c6
https://gerrit.wikimedia.org/r/49987

This should now be fixed.