Hawk August 22, 2017 This was a strictly-local update, from what I can tell so far, which means that it had no impact on the organic results located below the 3-Pack.
Possum September 2016
Google started filtering out listings that shared the same phone number or website, Google started filtering out listings that were physically located near each other.
It means that another business in your industry was in the same building as you — or even in the same neighborhood as you — that could cause you to get filtered out of local search results.
Hawk – Google refined the proximity filter to make it stricter. It still appears to be filtering out businesses in the same building, but it is not filtering out as many businesses that are close by.
Although it tightened the distance needed to filter a similar listing, it didn’t remove it completely. Its down to around 50 feet.