What does the bottom half look like? Do you mean the raised lip around the edge? Or the small spot in the raised part in the middle? I'm asking because I have seen magnetic closures like that before, minus the small circle in the middle. It might be how they attach the magnetic part and they solder it shut?
Here's an example of what I mean (from another brand). It has a raised lip on the edge and a screw in the middle for attaching the closure to the bag. It's raised in the middle to help secure it to the bottom which has a hole.
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Yes the raised lip around the edge on your bag. The pic you showed looks exactly like mine. I'm glad that's normal then. Thank you for letting me know!