Passing some Unicode characters to Linux Qt applications

[PCXT]

There are two things:
1. I'm doing it from Qt application, but it has smaller meaning.
2. It cannot insert character to any Qt5 application - even to itself. That's why I'm thinking about Qt misconfiguration.
The last character I can pass, if U+FFFD, all bigger code points fail (I think the last is U+FFFF, but it's not character by standard).