Was the bot filter active?
As there are two new very active ones, that seems more common these days.
There is an additional change that I should deploy to try to help with vehicle / movie / comment posting, but I haven't had time this week, I'll try to do that this weekend.

In addition to that, since yesterday there was a Russian IP trying to find security issues on various pages with an automatic script, quite useless but he was quite persistent. I blocked that IP, but if he changed, then it would also slow everything down. I really have to put in place some automatic detection of abusers.