FIDO Registration Passwordless - When the page focus is removed from verifying user presence, registration fails

Question

Hello
We are in the process of implementing FIDO for an organization and currently testing various use cases. i wanted to list down a two I came across and was hoping someone can provide more clarity on the behaviour by explaining this to me or point me to some links to read more about it ( did some digging but not seen any good explanations yet :))

Senario 1

1. User logs into aka.ms/mysecurityinfo
2. select to register security key
3. user is asked to enter a PIN or create a new PIN if he has not already
4. user is asked to touch the key to verify presence

on step 4 if i click on another page or click on my open excel/word document and the screen focus is now on this new page and proceed to touch my FIDO key to verify user presence i get an error message saying i am using a private browser session and my key is not registered.

This happens all the time and was wondering why this happens or if its a bug?

Senario 2
The expected behaviour for PIN bad attempts is 4 bad PIN inputs user is asked to remove and reinsert their key. They have another 4 attempts after this.
I have noticed that if i enter 3 bad inputs and proceed to enter the right PIN on my 4ths attempt i am still not allowed to login. I get too many incorrect PIN attempts to remove and reinsert your PIN.

Wanted to know if this is expected and can be changed or a limitation of the protocol?