Chrome DevTools script blackboxing not working

Question

I am trying to use the new feature of chrome devtools \"blackboxing a script\".
This Chrome Devtools article lists script blackboxing functionality

What happens w

Answer 1

Had the same issue and used good old

have you tried turning it off and on again?

Go to developer tools settings -> Blackboxing -> Remove all entries one by one + disable Blackbox content scripts

Blackboxed again and after that this works fine.