Just to follow up - I never did get to support but, mysteriously, I can now submit previously unsubmitted sites again, for review. At no stage did I have a problem adding comments to reviewed or unreviewed sites that had already been submitted, just with getting SA to accept *my* nominations for review. Now, automagically, I can again.
I have always found the submission pages - more particularly the log-in process - flaky (log-in not "sticking" when trying to add comments) but with peseverence always make it in the end.
This problem was (seemingly) not log-in related since submission for review can be anonymous, that's the way I usually do it, then log in to add comments pending review if I have any.
But logged-in or not I could not submit anything for review, therefore was not able to make comment (unless it had already been submitted for review by someone else). Starting with charmeddeals.com, which someone else has evidently submitted since. But I have been able to make my own submissions again, for some days now.
I see a more recently-started topic where someone else was having a problem too. That may or may not be related but from my perspective the interface is a bit of a 'bear', regardless of browser. Some days all is fine, others I have to work at it. But at least I can contribute observations on 'new' pests/threats again.
Prattling on here because I would think it probable that others are, and will continue to be, similarly affected from time to time. From my experience it (whatever 'it' is) seems intermittent. Which is at once a consolation ('this too will pass') and a frustration (what the heck causes it and how can it be fixed or avoided?).