@roms42 for a free plugin I’ve made the same as 7am did (https://support.advancedcustomfields.com/forums/topic/google-maps-field-needs-setting-to-add-api-key/#post-40317). I’ve added my Google API to input.min.js, and that is all. Perhaps you’ve made too many changes and something causes an error.
roms42, Please check have you enabled all the features for Google API key.
– make sure the Google Maps Api’s are enabled:
Google Maps Directions API
Google Maps Distance Matrix API
Google Maps Elevation API
Google Maps Geocoding API
Google Maps JavaScript API
Google Places API Web Service
Google Static Maps API
Bajaczysko, my answer is not a solution of a problem, please keep issue unsolved – so developer can see this issue and fix it in next update.
The Google Maps APIs require an API key for new domains as of today. See announcement: http://googlegeodevelopers.blogspot.com.au/2016/06/building-for-scale-updates-to-google.html
For developers: I think Google Maps API key should be added to ACF settings and used calling Google Maps API.