Bugs on Drupal 7 are fixed by cleaning the theme's registry cache. What caused?

Question

Google Play

Hello. The situation is as follows: a site on Drupal 7. Periodically, an error appears in the footer: "An unexpected error occurred on the site. Please try again later", while some of the layout elements in the header are moving (the logo is doubled). Only clearing the cache in the admin panel helps, namely: the "Theme Registry" item.
Tell me, what could be the reason for this and how to overcome this bug, so as not to periodically clean the caches?

Answer 1

This is fine?

fine

Answer 2

There is a question mark somewhere nearby, and there is a bubble on it - "the review can take up to 7 days or more."

Answer 3

Under 18 indicated?
3 days
Under 13 ?
longer and more likely to fail