obsm* conflict with metal* on gds read (sky130)

[d-m-bailey]

No error with magic 8.3.465 and open_pdks 1.0.470 With magic 8.3.478 and open_pdks 1.0.488 there are many errors like these in the gds read feedback

box 600480 580159 600800 580240
feedback add "Illegal overlap between obsm4 and metal4 (types do not connect)" medium
box 599792 580159 599800 580222
feedback add "Illegal overlap between obsm3 and metal3 (types do not connect)" medium
box 599728 580159 599792 580222
feedback add "Illegal overlap between obsm3 and via3 (types do not connect)" medium

This is because, for example, obsm3 and metal3 are defined on the same plane, and 2 shapes can not overlap on the same plane, correct?

obsm* and metal* often coexist (at least cross-hierarchy - macros are sometimes covered with obsm*), so maybe the obsm* should not be defined as existing on a plane.

EDIT: obsm* in the tech file appears to only be related to the waffle drop layers. Obstruction layers used in LEF files for routing are do not appear to be recognized by the current magic tech files (from klayout metal1/blockage 68/10, metal2/blockage 69/10, etc.)