We have had this before on linux. First thing to say is make sure your graphics drivers are up to date then let us know if the issue still persists
I think Apple manages the graphics drivers for you on MacOS. Unless you're using a Hackintosh or eGPU, out-of-date drivers aren't usually a concern on MacOS as long as you're using the most up-to-date OS release. With that said, the current stable for Mojave seems to be 10.14.4, while the OP is using 10.14.3 so....
I cannot reproduce the lighting issue on my Mac. However, I did notice a weird issue when scrolling in the overworld formicarium. Scrolling down to the bottom in the formicarium overworld leads to a black screen but with UI elements intact (scroll from "normal-scroll.jpg" to "black-scroll.jpg").
Another graphics issue I see on a Mac seems to be a transparency issue. See comparison between "formicarium-tank-macos.jpg" and "formicarium-tank-windows.jpg". The tank borders are completely black on Mac instead of the blue-green glass on Windows. I haven't tried the game on Linux yet, though.
In any case, here are the specs for my MacOS machine:
MacBook Pro (15" 2017)
Core i7 2.8GHz
16 GB RAM
Intel HD Graphics 630/Radeon Pro 555
Side note: My Windows machine(s) isn't my MacOS machine, and my primary Linux machine is another one, just to be clear.
Edit: Anything outside the formicarium's edge background for formicarium overworld #1 seems to be completely black on MacOS, so if there's a "suddenly visible" glass while scrolling down to the bottom edge of that map (formicarium-borders-macos.jpg), it's probably the same issue.