This is my solution for now: In the business location-block I add some data-attributes to the html output. In the maps-block I basically do nothing, except parsing each (in my case: li) li.location for these data-values and add it as markers to the map. This works in the frontend only, but it works.
Oh my, this feature cost me headaches. The script works, I can confirm that.
Okay, I rolled back to a 4.* version – fields where there, but this should not be a solution.
I edited wp_options → acf_version to “4.4.12” and performed a DB-update on the site that was causing the problem. Did not work.
Then I went through ALL subsites on a database level (wp_1_, wp_2_, etc.) and changed all wp_options.acf_versions to “4.4.12”, even on sites where I do not use the plugin actively. So in the end I had to update ALL of them.
I did that in one go and this did the job. My fields are back and everything works as it should.
It seems that if the update failed on one of the sites, all sites suffer. Hope, this helps you guys, too.
I have rolled back to the last 4.* release and so fixed the problem, but same here on a multisite. Also, I have never seen the upgrade database-message.