Comment (by Yosef Zlochower):

The attached thorn simply registers and array with for evolution with MoL. The thorn is not intended to actually evolve a real array. The issue also only shows up if the number of refinement levels is larger than 1

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2534/evolution-of-grid-arrays-with-mol-no