Duplication of the histogram: image offset of ASI533mc

I am worried about the interpretation of a histogram of an offset image.

Without offset in the camera configuration, the histogram is normal but with a truncation at 0 ADU (see attached image)

Now I introduce a minimum offset of 5, and there I see a sort of duplication of my histogram of the Bias image. (see attached image).

How to interpret this result? Is it normal?

Thank you for your reply?

It's normal in the histogram that has a truncation at 0 ADU. And could you please send your original image to us.