The line-gap property for MBStyle produces unexpected results.
This produces: A black stroke of width 12, a white stroke of width 11, and a black stroke of width 8.
What I would expect - Either:
Two black strokes (width 8), one with a perpendicularOffset of -6, the other with a perpendicularOffset of 6 (6 = 1/2 (width + gap) = 8+4 / 2).
One black stroke of width 20, one white stroke of width 4 (only as a workaround if the former doesn't work)
Resulting visuals attached (There is some other styling on that screenshot, only the big black line is the issue here)