Hi Mark,
The problem started when upgrading from PS 4.0 to PS 4.0.1. The PS 4.0.1 setup has instructions to manually run an SQL statement for meta tags (keywords,description,title). I ran it and got and error shown in this thread.
showthread.php?t=16657
I did run the SQL statement at least one other time to verify it gave the same error.
I believe running that SQL statement and the one found in the thread above cause the issue I was having.
The PS4_contents table had duplicate entries for meta tags and the ID's in the table were mixed up.
I was instructed to empty the PS4_Contents and PS4_ContentHistory tables.
Then I had to manually add specific lines from the PS 4.0.1 db.sql file.
Then I had to manually add back all the custom code from a backup of an SQL dump file to get my store looking the way it did before.
Jason