Some text attachment get added line breaks when emailed

We are finding a fraction of our the text attachments (mostly .csv files, maybe 10% or 20% of the time) our users upload end up with extra line breaks between each line when emailed. A CR LF is getting turned into a CR CR LF within the file.

This is only happening with the version of the file being emailed. If we log into RT and download the file there it is returned identically to what was uploaded.

Anyone else run into this? Or have a solution? We are seeing this at least since 4.0.22 and as recently as 5.0.5 (latest we are on). We have tested someone else’s 4.4.6 versions and saw the same thing. I’ll be trying 5.0.7 in the near future but don’t see any notes, so I’m not hopeful.