Google has added a disclaimer to the appointment provider links that you find in the Google Search local panel and in the Google Maps business listings. The disclaimer partially reads under the "about these providers," adding "providers are listed in random order."
It continues to say "however, if the business has specified a preferred provider, it will appear first." Then has a learn more link that goes to this page and that reads:
How providers rank for local business links Third-party providers can link from a business’s Business Profile on Google Search and Maps. These are called local business links. You can use these links to book an appointment, make a reservation, and place a food or shopping order with a provider.When multiple providers supply links for the same business, Google lists them in random order. If the business specifies a preferred provider, that provider shows first.
For food orders, Google also lists providers in random order. However, if the business's website is available, or the business specifies a preferred provider, those show first.
When you use local business links on your mobile device, business preferred providers are labeled as such.
Here is a screenshot that you can click on to enlarge:
This was spotted first by Damian Rollison and posted on Twitter:
New to me -- "About these providers" seems to be in reference to the appointment booking feature. Calls out the business's ability to specify a preferred option (as in food ordering). pic.twitter.com/sS21jWJ8H6
— Damian Rollison (@damianrollison) December 6, 2022
I believe this was triggered (I can be wrong) based on the latest issues around third party appointment systems hijacking listings in Google Search. Danny Sullivan was all over that and probably got Google to add a disclaimer, which is helpful and useful.
Here is an example of one that shows more than one appointment booking provider, with ZocDoc coming up as the second option:
Forum discussion at Twitter.