Joining these edges requires a joining tolerance of

I don’t know why but when I try to merge faces of this surface Rhino will not do it. Running JoinTwoNakedEdges will show me this dialog:

Also when I select one of the edges and try to move it I get this

Could someone explain me what is going on here? Thanks
mergeAllFaces.3dm (67.5 KB)

not sure where you took that screenshot, but if you split as indicated and join, then run MergeAllFaces, it works.mergeAllFaces.3dm (96.9 KB)

Thanks Gijs for taking a look a it. Yes, splitting the surface and joining it solved the issue, but I don’t know where the issue came from… The screenshot is from

as I was trying to get rid of one of those edges.