🇺🇸United States @kevinwlu

Solution found:
In the POST request json body, for the metatag field, enclose everything in "value" like this:

      "field_custom_metatags": {
        "value": {
          "abstract": "This is a page to test coh_event deployment. ",
          "content_language": "en",
          "geo_placename": "Tucson",
          "geo_position": "32.23298190321497; -110.95011213068365",
          "geo_region": "US-AZ",
          "icbm": "32.23298190321497, -110.95011213068365",
          "keywords": "test, coh deploy, college of humanities, event entity",
          "robots": "index, follow, noimageindex",
          "shortlink": "https://goo.gl/maps/qZGCcjVQxHzANEx19"
        }
      }

kevinwlu → created an issue.