I’m way late here, but in case anyone needs this – I built a plugin for this.
https://wordpress.org/plugins/ajax-load-more-for-acf/
Hope it helps others.
Ok, I actually solved my own question.
The issue is when you select the following:
Show this field group if
Logged In User Type = Administrator.
http://cl.ly/image/0t0q0e3M090S
Weird!