Similar as above for me. Scrolling the hotbar often takes multiple wheel ticks to do in 1.13, but is fine in 1.12.2. On macOS 10.13.6, using a SteelSeries Engine 3.12.9 with a Rival 100 mouse.
I did try setting mouseWheelSensitivity to 4.0 and it didn't seem to make a difference. Tried 20.0, and it works nearly all of the time - there still seems to be an issue when I change scrolling directions. So I tried 40.0 and that appears to always be consistent. I've probably exceeded some upper threshold value, but that worked for me.
Still present in 1.14.4 prerelease 3.