Sugar cane generation does not appear to work correctly in the latest release candidate. I found a sugar cane floating on top of a lake in 1.16-rc1. I used the exact same seed on 1.15.2, went to the exact same coordinates and found no sugar cane there.

Seed & coordinates:
1493028
-85 70 -79

Possibly related to MC-610, but definitely not the same bug, since sugar cane, to my knowledge, generates after the lakes have already generated, as opposed to structures and tall grass, which generate before the lakes.