On the forum issue and MacOS this is the same regardless of what browser I use. I have tried it on Three different Mac's and two iPads. 

I can post text but if I add a picture the uploading window just gets stuck, I click out and I get a red banner at the top saying something about can't perform that action. If I try and post what I have typed it signs out of the forums showing the attached page with the error in the page description.

This is posted from my old windows PC....