Google may be testing a new thing of removing reviews from the local knowledge panel. There is no such official statement from Google regarding this but it seems that after successful test completion an official statement will come.
Image Source: Search Engine Roundtable
Currently, the above test is running all over the world. But it is not specific about as some people still can see the review and some can’t. It seems like only for some searches the test is running.
In 2016, Google runs the same test of removing a review from the local pack. At that time Google removes the review option from the map results.