First up: the org runs on lightning experience.
Via a button, a user makes a synchronous call out to an external web service that returns a file. This file is saved to the record on which the button is and afterwards, the user is redirected to this record.
The problem here is that the file is not immediately visible. It requires a page refresh for the file to show. This is rather inconvenient.
My guess is that the information of related records is stored in some cache and thus doesn't show the updated content.
I found this issue description (https://success.salesforce.com/issues_view?id=a1p3A0000001C8QQAU&title=data-not-updated-in-ui-after-an-apex-update-in-lightning-experience) which describes the problem but the workaround is for web components and not visual force pages, if I understand it correctly.
Is there a way to clear the cache in the controller or in a visual force page?
Thanks for your help! Dan