You can see in the table above that the percentage of homes purchased by absentee owners rises consistently from 2016 through the first half of 2019. According to these numbers, more than one-third of all home purchases in 2019 have been made by investors. Yet even with this increase in investor purchasing, the volume of home purchases in most major metros has been declining. That is a major red flag.
Indeed, had it not been for the aggressive buying by investors in the past two-and-a-half years, home prices would have already slumped in these metros. If you do not find this suggestion plausible, remember that it was the pullback by speculators/investors in 2006 and their dumping properties onto the market that started the housing collapse.