It does effect. My friend’s OnePlus 3 now has its 2nd replacement battery.

It’s a recommended method to starts tickle charging after 80% battery every charging method reduce the current & increase its voltage at tickle charging process this is a common stage & not exclusive for OnePlus Dash Charge.

Even iPhone 8 & newer device stops charging after 80% if the device is unusually warm if you’re using fast charging or wireless charging to help battery health.

But OnePlus Dash Charge doesn’t affect battery health or cause heating as much as QC2.0 or 3.0 which draws 9V but it does increase battery degradation compared to a 5W charger because Dash Charge can deliver up to 20W