Unusual page not found error

I'm not sure this is evenn an issue, but here it is.  I made a post to the home page feed on my site, with an attached pdf file. On a windows PC, clicking on the attached file thumbnail, displays the pdf file as expected.  However, on a mobile phone, tapping on the very same thumbnail, gives a page not found error.

Phone: iPhone 11, iOS 14.4.1

One thing I did, was edit the original post, deleted the original attachment, then uploaded a new attachment of a different file name than the original. I only became aware of the issue after i edited the post, so I can't say if the problem existed with the original post and file... I expect that it didn't.

Clearing all caches in studio did resolve the issue, but I'm not sure why the problem only existed on the iPhone.  Clearing all browser history on the iPhone did not resolve the problem.

I know clearing the cache in studio is an easy fix, but standard members won't be able to do that.  I'm curious: Is the cache ever cleared automatically on a periodic basis?