when not using the keep HTML when replying, the message get's wrapped at 80 columns, even if the setting for this is unset. I'm using KMail version 5.0.2 in Kubuntu 15.10. Reproducible: Always
If any text is selected, thus quoting just the selected text, then the wrapping does not happen, when set not to happen.
This bug has never been confirmed for a Kontact version that is based on KDE Frameworks, except possibly a Technology Preview version 5.0.x. Those versions differ significantly from the old 4.x series. Therefore, I plan to close it in around two or three months. In the meantime, it is set to WAITINGFORINFO to give reporters the opportunity to check if it is still valid. As soon as someone confirms it for a recent version (at least 5.1, ideally even more recent), I'll gladly reopen it. Please understand that we lack the manpower to triage bugs reported for versions almost two years beyond their end of life.
I don't remember reproducing this recently. How ever, I'm currently on a KMail break, since for work I need MS Exchange now, so, take this with a grain of salt. I'll close it, and if this still happens, I hope someone will reopen it.