Have you ever encountered some data discrepancies using your Google My Business source? This might happen if you check the date range that includes the last 3 days.
Unfortunately, Google My Business API has a 3-day delay compared to the website data. Therefore, you might be missing some values when comparing data you see on Google and in your report.
To better visualize this, here's an example of the graph with the date range of "This month (incl. today) ". The last 3 days are not showing any data from the source: