In episode 253 of the weekly Hump Day Hangouts by Semantic Mastery, one viewer mentioned Google's updates on limiting 20 listings on the GMB dashboard.
The exact question was:
Hi Guys, . . . I can't thank you enough for the help you provide on Hump Days, so thank you VERY much AGAIN (smile) . . . . I'm sure you probably know this already, but Google is now limiting the total number of GMB listings shown to just 20