The Drupal core search form block breaks(fails to submit) sporadically.
Here is the background.
The site is a Drupal 8.0.5 multi-site.
I have the default search form block in the header and it works fine most of the time. But, nearly randomly, it breaks. And by that I mean you can type in search words, but the form will not submit. Pushing enter or clicking search submit gets no response.
It is mostly random except for a few rules.