Xamarin Forms - Back button spamming

Hi all,

I'm pretty new with XF and now I am having an app with a navigation stack with many pages.
The problem I have is that if I spam the Back button/arrow fast, the stack is not getting popped properly i.e at root page but the stack count still 4
This results a crash when trying to go next again

I am just wondering if there's some practice to handle the Back button that I've missed?

Cheers,
H