Cannot Snap on Midpoint on SrfEdge or Curve

Hello all,

Can someone help me with the following.
I received a rhino model (which was built in Rhino) and i am not able to select mid point across the edges of the openings.
Even if i dupborder I cannot snap on the mid of the created curves either.
If i create a new curve it snaps without any issue…

I have checked also for BadObjects and this is not the case.

Can you please advise?
I m working in Rhino6 but i have also tried the Rhino WIP with no success.

no_mid_.3dm (343.5 KB)

Hello - this surface most likely came in via iges file format at some point in the process - just a guess… the edge loops are single curves not polycurves or polylines.But in any case try this:
SimplifyCrv on the result
PlanarSrf (and delete the original)