Weird font problem in preview pane

I don't know what I did that caused this (because it wasn't doing it earlier today), but I can't figure out how to fix it.

In the preview pane, plain text looks like this:



When I open the message, it looks like this:



That's a new message I created to make the images, but incoming plain-text emails have the same problem. I've tried changing the fixed, proportional, and mailbox summary fonts, but the problem persists. It's only happening in Pandora, not Eudora or anything else. I'm on Windows 10, Pandora 5.7.0.1 64-bit edition.

Help?

(h/t to the Pirate Ipsum generator, https://pirateipsum.me/ )

Not sure what I did, but playing with fonts again seems to have fixed it. And I can't reproduce it. ¯\_(ツ)_/¯

So, not a problem anymore, but leaving it here in case anyone (including me) ever has an idea what caused it.