Lockdown Mode, a train wreck!

I have a Mac mini M1 that was working well until recently. Then I began behaving badly. I first noticed it when I tried to edit my website, some PDF files would not display, menu items would not be defined and only identified with a small empty square. Then I notice that the ability to eMail a page was absent. Then I noticed that I was in Lockdown Mode (appeared next to the symbol for sending a page).

So I went into settings (privacy and security) and turned it off. Now all is well with the world.

I was wondering if others had had this same problem?

How did I end up in that mode if it was an option?