Thank you guys for pitching in. No, this didn't have to do with moderated comments. If they are moderated, right after posting you get that message saying they will appear after the author's approval. What happens is what Jo says: the comment appears to have gone through, but is, in fact, lost.
I set my phone not to remember form history and passwords while playing with Settings, and so every once in a while, randomly it appears, it forgets I am Mira and I have to post a first comment and THEN sign in since on my phone there's no way to sign in from the beginning (I only have Pages and Authors at the top of the page on my phone). After I sign in there's no problem, of course (all the messages show up).
Also, I tried to write on this forum from my phone and couldn't. The field for the post title worked, but I could not get the field for the body of the comment active. It might be my terrible phone. I was tapping to write the message but it didn't work: it began to write the message in the title field as well.
(I'm now writing from a laptop. God, it feels good! But it was fun reading articles on my phone as well. Wizzley works great, actually, on a phone.)
Thanks again!