Google’s John Mueller was asked if the Google May 2020 core update or any core update can have an impact on the Google My Business reports. He said no, core updates in Google Search are unrelated to Google My Business. But yes, we did see many local search ranking changes before, during and after this Google core update was announced.
Here is what John said:
The changes in Search from a core update wouldn’t affect the availability of data in Google My Business. If you’re seeing changes there, I’d recommend checking in with the @GoogleMyBiz folks or their help forum.
— 🍌 John 🍌 (@JohnMu) May 14, 2020
It is a similar question to this one that asked if Search Console data tends to lag around core updates, which Google said no to.
Google Search and Google Local are pretty separate, they are a bit more aligned today in that some algorithms used in search can be used separately in local rankings. But either case, they are pretty separate.
Forum discussion at Twitter.