One or more pages were displaying terribly as though a style sheet were missing.
At the same time we were getting numerous error notifications from w3 total cache pluggin indicating that a style sheet to cache was missing.
Contact Ben at Beaver Builder who suggested we clear both the w3 total cache cache and the Beaver Builder cache.
We acted on the suggestion and all appears to be working.
To clear Beaver Builder cache:
In wordpress go to Settings/Page Builder/cache