I've twice tried to post comments to blog threads and I've been able to sign in and post both times. (I check the "remember me" box just because. And I had begun fresh browser sessions both times.)
The posting time was a little longer than I recall it, maybe 10 seconds. But it did post. In theory, a patch by the blogging software maker was to be put in place on Friday.
I'd appreciate hearing from others, particularly those who've been having trouble.