The check for existence of custom data layers did not take wrapper nature of mesh into account. Quickest and safest for 3.1 solution is to take care of branching of checks in the draw manager. Ideally both wrapper and mesh access will happen via the same public API without branching in the "user" code. That is something outside of the fix for the coming release though. Differential Revision: https://developer.blender.org/D14013