For such a long time now, I’ve been getting this same message being sent to my error log for my X sites:
PHP message: PHP Warning: count(): Parameter must be an array or an object that implements Countable in …/wp-includes/post-template.php on line 317
It doesn’t break my site, but it gets annoying having the log fill up with this stuff. I want to recall on a prior post that this was going to be fixed in a future release, but I can’t find it anymore with the new forums.