I’m using the 30 day trial for Glyphs, and when I copy from Illustrator into Glyphs, it doesn’t paste anything. Then the tab at the top in Glyphs says “Generator Adobe Illustrator SVG Export Plugin svg version” followed by a bunch of letters. Sometimes I can paste without any issues, but more and more I’m unable to paste.
Could it be you pasted text in text mode? Make sure a layer is open for editing.