The reply button is in the wrong place on this forum. In most apps and websites and forums it is placed at the bottom right of the text box as this is the natural point closest to the end of your message. This is accepted as a standard and as good UX. Yours however is in the bottom left, and you have an image upload in the bottom right instead, this causes many people included myself to press the upload button to send the message. If you only had one button you could choose to left align if you really wanted to go against standard UX guidelines but if you have more than one, like you do, then the reply button, being the primary action should be the button that is on the right.
It is when viewed on a phone to be fair, not that it bothers me in the least I might add, but what he’s saying is correct.