it has a quick flash but but does not place. Ends up back in hand.

I am having this same issue

As am I.

Closing as should be a duplicate of #110

Having the same problem in 1.16.5. You just closed the issue because it's a duplicate of itself.
What I was able to do is to place some other bunting first and then replace it with the letter bunting by clicking on a string.
I think the problem is that when i crafted it the text says {"text":""} which contains invalid characters and that's why you're unable to place them. The check is not in place when replacing, so you're able to replace the bunting and then change the text normally. After breaking the correct bunting, you can place it anywhere as expected