Sculpting on Edge of Landscapes produces Random results on Mac

When sculpting on the edges of landscapes, the changes in the landscapes height can be random and inconsistent.

The user reporting this issue tested on an iMac 5k with AMD Radeon R9 M395X 4096 MB.

1. Create new blank project.
2. Create new landscape with default settings.
3. While in 'Sculpt' mode, place the brush on the edges of the landscape and left-click.

Outcome The landscape has random changes in height along the edge when sculpting. (See attached GIF)

Expected The height remains consistent while sculpting