Email delivery failure: BareLinefeedsAreIllegal

I was wondering if anyone else ever came across this? We have users reporting bounce emails from Office365:

Reported error: *550 5.6.11 SMTPSEND.BareLinefeedsAreIllegal; message contains bare linefeeds, which cannot be sent via DATA and receiving system does not support BDAT*

We are sending email from lucee using an Office365 SMTP account in this example. It seems most email delivers without issue, but sometimes - the sender will receive that bounce report. The recipient email address varies, but this example was a Gmail one.

Your message contains invalid characters (bare line feed characters) which the email servers at don’t support.