Because the prime symbol (') is reserved for time reversal in magnetic Hall symbols, the first primes in these symbols should be removed. https://github.com/spglib/spglib/blob/f0db532d91b3e02915468d8e5ad9f848ca1e4bd5/database/msg/magnetic_hall_symbols.yaml#L414-L416 I've checked these parts does not affect C implementation itself.