I have been experiencing the same problem as the OP for quite a while now. So I simply stopped writing anything at all in the comments box as I couldn't find a way to ask for support. But that's not the permanent solution as I have every now and then something to say. :( And just like OP, my likes seem to work and they still appear but my comments are posted and shown on the page till I refresh(reload) the page aaaanndd its gone. Just now I posted on the Sony shares slide most in four years and it just didn't work at all. Stupid of me that I was looking for a "contact us" link or something of similar for the support and it never occured to me that it must be in the forums. Really sorry for that.