Interesting! Here's my browser info: My browser / operating system: MacOS Macintosh X 10.15.3, Chrome 83.0.4103.116, No Flash version detected
Weird. It's like the “%” and Input glitch, but it doesn't freeze the entire editor, and can actually use the block.
Edit: It freezes the editor, you just have to look at the blocks section.
My browser / operating system: MacOS Macintosh X 10.15.5, Safari 13.1.1, No Flash version detected