Archiving from Apple Mail - DT3 seems to insert "invalid" tab characters in subject/name

Archiving from Apple Mail into DT3 is working for me, but among the many thousands of emails successfully archived in DT3, in the case of a few hundred emails, a space between words in the subject line is getting replaced by some other “invisible character” that causes a weird combined tab + line break effect when viewed in the Name field in DT3 (and in the Finder). The problem is that when my backup software (Tresorit) later tries to grab these files from the DT3 database among all the others files there, it flags them as containing an “invalid character” (described as a ) and refuses to process them, while processing everything else in the same DT3 database without complaint. I can’t identify anything about the subject lines of these particular emails that is different, and I can’t figure out any way in DT3 to do a find and replace that could fix this “invisible character” en masse. (Fixing each one manually in DT3 would take many, many hours). Any suggestions?

Select a small sampling of the emails that cause the issue and drag them to your Desktop. ZIP them. In DEVONthink, hold the Option key and select Help > Report Bug and attach the ZIP file.