This, given then nature of the error message, seems to be related to MDL-72837.

In a couple of testing sites that I've around (pointing to integration.git repository) and that I had not visited since some good days.

• Not being logged.in.
• Visiting the main (/index.php) page.
• I have got this:

  Error

  Coding error detected, it must be fixed by a programmer: Unexpectedly found non-versioned cache entry

  Debug info:

  Error code: codingerror

  Stack trace:

  line 464 of /cache/classes/loaders.php: coding_exception thrown

  line 511 of /cache/classes/loaders.php: call to cache::check_version()

  line 1787 of /cache/classes/loaders.php: call to cache->get_implementation()

  line 436 of /cache/classes/loaders.php: call to cache_application->get_implementation()

  line 478 of /lib/modinfolib.php: call to cache->get_versioned()

  line 441 of /lib/modinfolib.php: call to course_modinfo->__construct()

  line 2242 of /lib/modinfolib.php: call to course_modinfo::instance()

  line 65 of /blocks/site_main_menu/block_site_main_menu.php: call to get_fast_modinfo()

  line 787 of /blocks/moodleblock.class.php: call to block_site_main_menu->get_content()

  line 235 of /blocks/moodleblock.class.php: call to block_list->formatted_contents()

  line 1222 of /lib/blocklib.php: call to block_base->get_content_for_output()

  line 1280 of /lib/blocklib.php: call to block_manager->create_block_contents()

  line 377 of /lib/blocklib.php: call to block_manager->ensure_content_created()

  line 4028 of /lib/outputrenderers.php: call to block_manager->region_has_content()

  line 54 of /theme/boost/layout/drawers.php: call to core_renderer->blocks()

  line 1435 of /lib/outputrenderers.php: call to include()

  line 1361 of /lib/outputrenderers.php: call to core_renderer->render_page_layout()

  line 120 of /index.php: call to core_renderer->header()

  

Workaround: Just reload the page and the error is gone. So it seems that it only happens once.

But it shouldn't happen ever.