If I upload an image, and cancel the upload, it can get in a stuck state:
The spinner is still spinning, but is clearly never going to finish, and I can no longer press Reply when stuck in this state,
If I cancel the reply, and then click reply again, it is still stuck in the state, although now it says “Uploading 0%”.
I have to reload the page to get it unstuck.
This is Discourse 1.8.9, Safari/Sierra (10.12.6)