In Classic we used to have Visualforce page overrides for the Account, Lead, Case, ... tabs.
Now that all our users have migrated to Lightning, we want to remove all Visualforce pages. The first step is to remove the Override for Standard Tab Home Pages. Here is the documentation on how to do that.
When you actually do this, you will notice that you must select the "Use the Salesforce Classic override" option for Lightning. You cannot select nothing. For Classic, this just works. But in Lightning, when you go to, let's say, the Opportunities tab, you get a Lightning version of the Classic Opportunities tab. It looks weird:
The only way to get the Lightning Tab view back (we have never used tab overrides in Lightning), is to refresh via Ctrl-F5. I have tried several other methods, including completely closing the browser, but that was never enough. I always had to refresh via Ctrl-F5 to get the Lightning view.
I do not want to "surprise" the users with this experience, I would not like them to contact our support department about this, and I really would not like to send a mail to all users telling them to press Ctrl-F5 when they see strange screens.
Is there a way to make this transition less awkward?
UPDATE: I see a related question, and the strange thing is: all standard object tabs were overridden in Classic by Visualforce pages and for all these tabs, the Lightning setting already was: "Use the Salesforce Classic override"
But that is not what we saw in Lightning, we always got the standard Lightning tab views. Until I reset the Classic setting to "Standard" and all of a sudden we see Classic views in Lightning :-(
Enable secure and persistent browser caching to improve performance. That, obviously, might not be an option for you in production to turn off - but, if you have a support case might be helpful for reproduction steps.