Scratch Pad - corrupting RTF files

I’m tearing my hair out with this. I’m trying to make it so I can write new/edit existing Scratch Pad notes using my Android phone with the Scratch Pad synced through Dropbox. I’ve found an Android app that edits/creates RTF files (TextMaker) and it syncs perfectly with the Scratch Pad folder. Tested the new and edited files out in Windows and they open and look fine but whenever I open them in Scratch Pad it blanks out all the text - all the text is blocked out in black as if someone has redacted it all with a black marker. Then, when I open the files in Windows again, the text is, again, blocked out and can’t be changed back to regular text (it’s not a case of simply selecting the text and changing the font.) It’s completely unusable.

I’ve even tried setting the font the same in TextMaker as it is set to in Scriv/Scratch Pad (Courier New) but the issue persists.

So, I’ve no idea what is going on. Is there an incompatibility issue between the newly made RTF files and the Scratch Pad? Should I try a different app? If so, what does anyone else use?

Am I missing something obvious? Should I just contact the devs?

Also - I’m guessing the ability to use txt files in Scratch Pad is a Mac only thing for now? That would solve a lot of problems.