I tend to make a post and then serially refine it. Tonight, I could only make a few edits before an error started to block further saves:
inet_pton(): Argument #1 ($ip) must not contain any null bytes
Tonight this happened with one of my own initial posts and subsequently with a comment I'd made in another user's thread.
In the case of my own post, I then also noticed that the double quotes in my title became " [I was able to fix that the next morning, as noted in my comment, below]