Unable to disable Long Term Noise Reduction in Bulb mode?

Now I don't have NX10/11 or NX200, but at NX20 at bulb mode it is impossible to turn of long term NR, so it must be like this in all NX cameras.
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NX20, NX200, NX10, EX1, 20mm, 30mm, 18-55mm, 50-200mm, 60mm, reverse Mount Adapter, Galaxy Note
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