It does seem like GAG have put some updates on their mobile app which is not working consistently. Today, i have been seeing that SOMETIMES, instead of the old comment field at the bottom, a popup comes up for the comment; but mot always. Perhaps, it keeps loading that popup for you.
Not me personally anymore but I've heard of this happening to other people. For a while, I had problems submitting opinions and stuff with the same loading thing... I went into the bar where the URL is and hit enter. Sometimes the comment or opinion would be submitted and other times I would have to resubmit.