I have observed this trend too, especially when a reel is promoted far away from its usual target audience on the account. Even though the metrics might seem impressive, the follow ratio lowers bcz of users enjoy the single Reel without seeing any reason to view the account. i becames more interested in tracking the number of profile visits and follows per visit rather than focusing only on reach for the Reel.Yes, this is something that I have observed too. It is not necessary that reach converts to followers because most of the people view the reels and do not check out the profile anymore. Mostly the thing that makes the difference is having a theme in the profile and giving reasons to follow.