Sometimes my authentication pop-up doesn't pop up

System wide. Have to log out and log back in. Then it's back.

Are you referring to the Password Prompt for when you need to elevate an app to Root Privileges?
You might try

sudo apt install --reinstall policykit-1-gnome ca-certificates

Yes, thanks. I'll try it. It's the only bug I have.

Update:

What seemed to work is turning off auto Suspend (after an hour). Now, I only used Suspend when hitting the power button at night.

Update:

Well, that didn't cure it but it finally went away. Must have been a system update.

Now I have zero bugs.