it could be that your webhost does some extra caching that only gets refreshed after a set time
i had the same issue with someone else.
he updated all plugins and lay theme. he did all steps in the blue box, like if he used a caching plugin, he purged/cleared the cache in that plugin
but still, only old theme files were loaded while the new plugin files were loaded as they should.
but only the latest theme files were compatible with the latest theme files
i made an update like 1 or 2 weeks ago, where i needed to change many things in lay theme and in the addons. so the addons and lay theme both needed to be up to date for everything to work
he wrote his webhost and it turned out they cached something on their side and thats why part of the old files were still loaded
this update i did reduced the amount and size of javascript files that needed to be loaded for the frontend