Ok so secure folder worked perfectly before Android 11. Not only did that update remove some great features, it has caused so many bugs I am thinking of leaving Samsung for good.
Now, secure folder notifications, which I have set to show on the lock screen, but with hidden content, sometimes show randomly with content. Completely defeats the purpose of a 'secure' folder. It worked so well before and now I cannot trust it as some messages show correctly hidden, and others show the full content. It is from the same app so it isn't an app issue.
Secondly, Samsung removed the dual sim feature that allows me to dial a contact from either SIM by clicking on the phone icon for either SIM. Made it so easy to manage. Now I have to have it set to ask me every time I make a call. Why do you remove such good features???? It's insanity.
I don't have my S20 anymore because it continually got worse over time but this issue ticked me off so bad. I wasn't even using my secure folder and I kept getting these notifications constantly and it would say "hidden content". Not good when my wife was right next to me. She kept thinking I was hiding things. Ugh Samsung. So awful.
i never had a problem with secure folder content being show.
try download samsung members app and submit a ticket.
once you open, click +, then click error report
You have to go to settings in Secure folder --> Notifications and data --> App notifications --> Whatsapp --> Message notifications --> Lock screen --> select "Hide notifications"