Me again, I know the problem but not how to fix it. Gutenberg in WordPress 5.0 beta is on the core not as a plugin. If you install it as a plugin ACF works correctly.
Me too, I have the same problem, also I tested with both versions of ACF (current version + beta).
I have the same problem. And is a bit annoying when you have a lot of custom fields on the screen.
WP 4.9.8
ACF PRO 5.7.7