Comment (by Gabriele Bozzola):

I found this out possible problem. SphericalSurface_Set does not specify an AFTER statement for SphericalSurface_Setup. When I was messing around with the scheduler trying to fix this bug, I had cases in which Set was scheduled before Setup, leading to crashes.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2625/carpetmask-should-not-be-scheduled-before