On my site ciecha.pl the footer isn’t showing. I have all the updates. I have looked on support page and used all the solutions that are given there and still nothing. In the preview the footer shows, but not on the main page.
Try re-enabling the cache it may have just been the cache needed clearing after any recent changes / updates. If it still occurs then disable the various CSS options in the cache plugin to find out which one is the culprit.