Google has clarified on its Local Business structured data help documentation that when you want to specify multiple types in Local Business structured data, specify them in an array and do not use additionalType, which isn't supported.
Google wrote over here:
The full definition of LocalBusiness is available at schema.org/LocalBusiness. Define each local business location as a LocalBusiness type. Use the most specific LocalBusiness sub-type possible; for example, Restaurant, DaySpa, HealthClub, and so on. If you have multiple types, specify them as an array (additionalType isn't supported). For example, if your business offers multiple services:
Previously it said:
The full definition of LocalBusiness is available at schema.org/LocalBusiness. Define each local business location as a LocalBusiness type. Use the most specific LocalBusiness sub-type possible; for example, Restaurant, DaySpa, HealthClub, and so on.
I would scan through any of your code to see if additionalType comes up and where.
Forum discussion at Twitter.
