[Paul R.]

I believe there were a few web pages that I had to disable Brave Shields (ad blocking) to work.

Seems to be a common observation

This can be handled on a case by case basis.

So, once one "un-Shields" a website, does Brave remember that, or does the site have to be unblocked every time one goes back to it?

[Harmless Teddy Bear]

You can do it either way.

Add the website to a list you want unshielded always (if you trust it) or just do it once. Either is simple.

[JoeVortex]

Once you disable Brave Shields for a particular site the browser retains that setting until it is reenabled.