A few of our users are complaining of issues when trying to post using iPhones (5S and 6)
When clicking in the window it jumps away.
The whole text box starts hopping away from your touch to the bottom of the screen and from the bottom back up to the top. It can take about 3 goes before it settled down.
It’s a bit hard to reproduce reliably, but it’s definitely not stable
I have been able to repro it a couple of times on my 6+