error when using Unicode Private use areas supplementory A and B

[IsabellaB622]

Despite displaying correctly in most areas of the application PolyGlot Gives an error when using a glyph in the Unicode
Private Use area supplementary A & Private Use area supplementary B blocks when creating a word that uses that code point even though the conlang font supports it and it displays correctly.

here is the glyph being used as it appears correctly

below is a minimal reproduction of the issue as well as the glyph being used. (please note you may need to leave the lexicon tab and return to it for the error to appear)

minimal.zip

[synthfi]

which version of polyglot and what platform are you on?

[IsabellaB622]

PolyGlot ver. 3.5.1
GNU/Linux (Debian)