You still haven’t shown how the TextBlock is declared.
I’m assuming your listener code is actually:
"TextEdited": function(e) { e.subject.text = e.subject.text.split(' ').join('\n \u00AD'); }
The \u00AD
character is a “soft-hyphen”, so it should not be too surprising if you see a hyphen when a line is broken up into multiple lines. If you don’t want a line to end in a hyphen, don’t use that \u00AD
soft-hyphen character.