The issue is that Tixati sanitizes file names that begin with ~ because that is what linux systems use to denote a hidden file. They don't show up in the file explorer.
This is wrong, tilde ~ is only used as a special character by the shell ("the textual console" for you non-techies) as a shortcut for the user's home directory. The hidden file is ".dotname" and that's nothing bad either. (this is the first time I've heard about ~ being used for anything else)
KDE's file explorer (Dolphin) allows you to create a ~name but it shows a fair warning:
Starting a file or folder name with a tilde is not recommended because it may be confusing or dangerous when using the terminal to delete things.
If we are to be pedantic yet accurate, you can use ANY character except \0 (null) and / (forward slash) as a folder or file name.
On the other hand, tilde could
lead to problems if used on Windows improperly (the short 8dot3 format) but Tixati isn't susceptible to this. Still, Windows disallows more characters in file names and I think these cases should not be blocked (during creation) but warned about like Dolphin does on Linux.