On Macintosh, scroll wheel not working properly:

1 - When standing: Scroll wheel response is erratic. Scroll wheel (action bar) does not advance on a per-scroll-increment basis, unless you are scrolling quickly between increments. If you try to move just one scroll-increment forward, nothing happens. If you try to advance quickly, by double-scroll-incrementing, then the action bar advances, and any additional quickly advanced increments work fine.
2 - When crouching: Scroll wheel is NOT RESPONSIVE. The scroll wheel does not advance at all. You cannot change tools while crouching, at all. 

This issues has existed for months, and nobody has addressed it. The response of "adjust your scroll wheel sensitivity" is NOT a solution. Adjusting scroll wheel sensitivity does NOT fix the issue. 

The problem is present on Mac OSX, regardless of OS version. Minecraft 1.12 works fine, but Minecraft 1.13 is broken as here mentioned (still), when testing on the same machine, across OS versions. 

Please, fix / escalate! Problem is being ignored for some reason. Why?