Comment (by Eloisa Bentivegna):

Gabriele, Roland: I am afraid there isn’t an easy fix to this, without breaking some of the key use cases. If one is not interested in those cases, the offending lines can be simply commented out. The correct way to solve the problem would be to introduce a mechanism to register grid functions for restriction when necessary (moving the burden of ensuring correctness to the user). This has been on the thorn’s todo for a while, but has not been implemented yet.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2579/ct_multilevel-implicitly-requires