In Glyphs 3.0.2 (3055), some characters (like
√) in the feature code crash Glyphs. The following movie demonstrates this by opening a file containing such a character in Glyphs build 3053 and Glyphs build 3055:
Here is the test file from the movie:
Test.glyphs (5.8 KB)
I have also send a crash report linking to this forum thread.