Incorrect AltGr sequences through mosh

I noticed issues when trying to comment in nano and such, and figured out that when trying to type a # through mosh an empty character was added 

Through SSH when I type cat, enter, then AltGr+3, then interrupt I get
```bash
~$ cat
#
#
```

But Through Mosh it shows
```bash
~$ cat
^@#
#
```