Some things got fixed, but new huge bugs were also introduced with this beta 3. About two weeks to go, and time is running out, I almost feel sorry for the core devs as the pressure on them must be astronomic now...

https://wordpress.org/support/topic/wordpress-5-0-beta3-does-not-save-acf-metabox-data/

Also, still no custom buttons on the Classic Block, which is really important for shortcodes.