Hmm, very strange. You are right. I am still running the Open Beta version. What seems to have happened is that the game now creates a "DCS" folder under Saved Games and uses it. My Saved Games folder has been "DCS.Openbeta" for years and was still like that after the last DCS update. Now, it uses only "DCS". The only change I can think of in the meantime was making the change in my anti-virus software.
I moved all my Saved Games files from the DCS.Openbeta to DCS folder, and it now works normally. Thank you for you help.