Screen lock no longer works

Purism Librem 13v2
Ubuntu 20.04

Recently my session is not locked when the laptop is suspended.

I have checked all the relevant settings repeatedly and cannot figure out why the session is not being locked when the laptop is suspended.

Does anyone have any tips on diagnosing why this is not happening?

Thank you very much for any and all help.

Edit: I have been pushing Super + L to force a screen lock before closing the lid. However even doing this, sometimes when I open the lid again, the session is STILL unlocked!!!