Same here – WordPress 4.9.8 and ACF Pro 5.7.6. It looks as though the key (added according to the docs for acf_update_setting) isn’t being appended to the request to the Google Maps API. This has worked seamlessly for quite a while and appears to have only stopped working recently. Funnily enough, the address search function works and the value of the field is saved. It’s just that the map itself is covered by a semi-transparent dark overlay.
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