Wish I could provide more info but all I can tell is that it looks like ACF 5.0.5 (just updated from 5.0.3) is stopping execution of JS on at least user-edit.php. The symptom I noticed was that I could not change/remove the image of the user.
Chrome inpector says “cannot read property ‘attributes’ of undefined” for this:
I have the same error message with acf 5.0.5. But in my case one of my WYSIWG fields on a options page isn’t showing any of the regular buttons and the text is inverted to white on a white background. :/
One methodical question about the replacement. Do i have to deactivate the plugin before replacing and or do i have to switch off mamp in my local dev environment before the replacement? Best regards r.