Because the name is stored in a UNICODE format. So let's say your name is:
thethiny
in unicode your name is
t.h.e.t.h.i.n.y
so the program saves it as
t.h.e.t.h.i.n.y
then you save it, and load it again
it loads it as
t...h...e...t...h...i...n...y
then saves it as
t...h...e...t...h...i...n...y
then you load it again as
t.....h.....e.....t.....h.....i.....n.....y
so if your name is 1 letter, it will take you 5 tries before you hit the max character limit.
If your name is more than 1 letter, it will take less.
To fix this, once you load your save, just rename yourself correctly, as if if you see squares in your name, I think you have to remove them.
tl;dr
@xSillusx fix the Unicode encoding in your save file.
--------------------- MERGED ---------------------------