You can pretty safely ignore it, it's usually just UI lag. The only time I've seen it spin and not do what I told it to was when I was first trying to sign up for an account. Your comments and votes will go through.
Yep, I think you might have highlighted a bug, Certain it is happening in firefox , and is not present on the android app.Have learnt to ignore it , almost always my comment has been added.
Edit yep immediately clicked on comments open new tab and my comment is here where as it is still spinning in the other tab. So probably a bug rather than overload.
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