I contacted ACF support about this, in turns out upgrading ACF Pro to version 5.9.1 and upgrading WordPress to version 5.5.1 fixed the issue.
I’ve tried multiple browsers and it still throws the same error.
In the browser console it’s thowring the following error (screenshot):
Uncaught TypeError: can't access property "BlockControls", C is undefined acf-pro-blocks.min.js:1:9076
@levdbas was that in your functions.php file?