Faces of model has weird shadows

So basically, I'm trying to make a model (picture below) which is basically 2 cubes and 2 cross-model parts (ie. similar to minecraft's cross model / flower models). For some reason, and no matter what I do, the lighting on them is always messed up.

Notice how one of the panes in the cross model is fine, while the other is shadowed? Additionally: When placed while facing one direction, one of the columns has no lighting issues, while the other one is messed up.

Is there a way I can fix this so every single column on every side looks like that 'normal' one?

I've tried:

-> Messing with transparency types, block types, luminance, other MCreator settings etc.

-> Disabling ambient occlusion (didn't fix the issue)

-> Disabling 'shade' in the JSON file's code (initially worked, but then it got messed up whenever you place the texture in a dark spot next to other blocks)

Thanks for help in advance!