Codes of these characters match special keys of ncurses, namely
KEY_BACKSPACE, that's why they aren't handled as usual input.
I'm quite surprised that this issue wasn't found before, but it seems to be solvable. I'll just move all special keys to Unicode Private Use Area starting from
U+E000, which shouldn't clash with anything except for maybe iconic fonts, but by convention they start from
U+F000, so even that shouldn't happen. (Solution that guarantees no clashes ever is possible, but very inconvenient for implementation.)
There is no workaround for now, you'll have to rename such files on the shell. Development version will get the fix soon, just need to make sure I don't introduce new bugs by editing 500+ lines.
Thanks for the report!