Before I start even trying to explain this, it would be helpful to know what browser or browsers you and Glenn are using and where either one of these finds is not working.
I am going to try to make the distinction between a browser find and a screen reader find (and it doesn't matter whether it's JAWS or NVDA) as simple as I can. I can assure you that I will be omitting scads of "under the hood" detail that someone far more knowledgeable about both browser internals and NVDA internals can delve in to if they so choose.
A browser find focuses on what can be seen on a page that's a part of the page text. That is generally limited to actual text as well as text used for click-through links and labels. But text on controls, like buttons, checkboxes, etc., will very often not be found using a browser find. Much of this depends on how sloppy the page coders have been about how certain controls are written and what's exposed to a browser find versus a screen reader find. I also believe that a browser find does not examine the virtual cursor used by the screen reader while a screen reader find does just that.
As a result, there can be differences in not only what can be found by either one, but exactly where the screen reader focus is after each is done.
I tend to favor the screen reader find when someone's using a screen reader simply because it tends to find certain things that a browser find doesn't, and you more often have focus on the thing just found, consistently, with a screen reader find.
I'm actually hoping someone with way more "under the hood" knowledge will chime in and probably bore some of us silly getting into the actual differences between how a browser find and screen reader find works and can explain the discrepancies not only in what each can find but in where focus lies after each. I have never been able to come up with any precise way of describing what's different between the two.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
Always remember others may hate you but those who hate you don't win unless you hate them. And then you destroy yourself.
~ Richard M. Nixon