When replying to a post, the first click on "Send" results in a long spinning animation that eventually times out and displays a red error message, making it appear as though the reply has not been sent, but in reality, it has.
I thought I hadn't sent it, so I clicked "send" a second time, and this time it went through immediately. However, it showed that I had replied with two identical messages.
Additional note: My network connection is working perfectly.