Win 64 bit blender 2.80 / 2.81
If I create a Measurement line it appears a annotation layer named "RulerData3D".
If I rename that layer to something else the line becomes a normal annotation line without measurement data (no dashed line with measurement value).
Is that a normal behavior. That would mean all measurement data are inside of one notation layer and there can't be more with different layer names, colors or thicknesses ...