I know this sounds wacky....
I've just started seriously using LE. I have noticed that field updates didn't show up for a short time (like, 1 - 10 minutes delayed) in a few situations:
* I used the Mass Update appexchange addin to update a set of reocrds from a list view. The list view showed them with their new values, but visiting one of the record pages itself showed the old value. A handful of minutes later, the record page showed the new value.
* I used dataloader to update a field value on a set of records. I refreshed a report I had running showing those records, and the old field values still showed up. I visited one of the records and saw the new value. Then (maybe 2 minutes later) I refreshed the report again (using the LE report page's 'refresh' button) and the new value showed up.
I'm just going senile, right? I mean, it can't be SF, it has to be me somehow...
...I've never seen this behavior in Classic.
I have this happen all the time on demos. It usually resolves itself within a few minutes but you can always try a hard refresh.