When zone is enabled for, and only for Top and Bottom layers, KiCAD uses special "F&B.Cu" layer name instead of two layers: "F.Cu" and "B.Cu". This causes issues during serialization, as KiCAD requires "layers" token when combined with "F&B.Cu", not "layer". When this name is set incorrectly KiCAD segfaults.
When zone is enabled for, and only for Top and Bottom layers, KiCAD uses special "F&B.Cu" layer name instead of two layers: "F.Cu" and "B.Cu". This causes issues during serialization, as KiCAD requires "layers" token when combined with "F&B.Cu", not "layer". When this name is set incorrectly KiCAD segfaults.