Somehow, it looks like all dashboards are broken, but only with MRs.
See here :
https://gitlab.kitware.com/vtk/vtk/merge_requests/5919
https://gitlab.kitware.com/vtk/vtk/merge_requests/5682
https://gitlab.kitware.com/vtk/vtk/merge_requests/5918
While master build fine :
https://open.cdash.org/index.php?project=VTK
What is going on ? @ben.boeckel
vtk/vtk!5682 launched tests off a really old branch. That caused build failures since some cmake flags or build state needed a clean build to work correctly. Since we only do incremental builds on MRs (unless Do: test --clean is explicitly requested), all subsequent MR tests failed due to similar errors until a master build got scheduled and cleaned the build dirs.
Moral of the story: please don’t test branches that are too old, and if unavoidable, use Do: test --merged.
indeed ! I should have checked that before running the tests on this MR. thanks.
Yikes – “really old” in this case was master from just a week ago! 
I’ll try to keep closer to current master.
@allison.vacanti : No no, it was me. I ran a 3000 commit behind branch from an external contributor because I forget to check that. My bad.