Last month it was reported that a new bug caused businesses to lose all of their reviews after their Google listings were auto-updated. Mike Blumenthal has issued a detailed report.
According to the Blumenthal report:
What is the New GBP bug?
A lot of businesses are saying they lost all of their reviews after their listings were auto-updated. Here are some representative posts on the Google Business Profile Help:
Change in Profile and lost reviews : Suddenly I woke up to see that the details about my profile were changed and all the reviews were deleted. I am confused about how to approach this situation. Do guide me..
All Reviews Gone : On Friday (11/4) I got an email from Google that my business profile was updated. Much of the information changed was changed to incorrect information or just removed entirely. I went to review and undo many of the changes. Today I noticed that all my reviews are now gone. I had 18+ reviews on my profile and I need to get them restored but I don’t know how to go about getting them restored.
My genuine reviews have all been removed, 95 of them : 95 reviews have all been removed, even 5-6 1-star reviews. They also slightly changed my business; I was able to instate [sic] though. But I haven’t had no luck getting my reviews. Please help.
Customer reviews disappeared :  reviews were lost all at once. Google had automatically updated my business information. They had shortened the business name to (Sydney Steemer) without the carpet cleaner. And changed my website information to a different link that also went to my website. This when I realized all the reviews had VANISHED!
All reviews are gone : We had 170+ all 5-star reviews. One day they were all gone. In the settings it
showed that google changed the name and phone number and short name for our business. After trying to contact them with the issue for over a week we still are not able to get reviews back or any answer. Also, some changes that google made we are not able to accept or decline.
The report further says after running through the typical scenarios where one might expect to lose reviews it is clear that, in every instance, reviews disappeared immediately after the Suggested Edits update.
Mike discovered that in each case Google had changed the Customer ID Number (CID), the identifier Google uses to tie all relevant information to a business, including reviews. But this is unusual because CID only changes when two listings merge or Google has hard-suspended a listing for guidelines violations and then reinstated it.
Mike’s report goes on to say, “Changing the CID and losing reviews with a Suggested Edit update is a new and disturbing bug. It could happen to almost anyone for no reason or no apparent reason. Yet, in Google’s infinite wisdom, it could also be working as intended.”
We would suggest reading Mike’s report to learn what you need to do to recover from such an event if/when it happens to you.