Google may be pushing out a new Search Console feature where for the partial data, the most recent data it has, which was not yet finalized, shows up as dotted lines. Google always put a disclaimer on the most recent data that says, "Partial data point (fresh data) - does not cover the entire date" but the dotted line design in the chart may be new....
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Google Search Console Partial Data Reports With Dotted Lines
seroundtable.com