I'm talking to MPI and I will just copy/paste the email.

[MPI]
Hi Jake,
No, it is not normal and it is dangerous. The backplate of the spinner should stay flat. According to your picture, it is buckled or pushed in. There are two ways for this to happen. First, the cone is over-tighten which bent the backplate. Second, the back of the propeller interfere with the rim of the backplate. When you tighten the prop, the blade hit the rim first before the hub set on the backplate. As you continue tightening the prop until the hub is set, the prop continue to push the rim and bent the backplate.

No matter what type of spinner you use, the prop should be in contact of the spinner at the hub only. the blade should be clear from the backplate and the cone. If the bent is slight and within the elastic limit of the material, it will bounce back one the the pressures is released. If the bent is beyond the yielding stress, the damage is permanent. You will need a new backplate. If you are not sure about the condition, it is safe just replace it.
Regards,
Jarvis Yeh
Maxx Products

[Jake]
Hi Jarvis,
Thanks for the reply.
You mentioned 2 possible cases how this happened.
The first case is not quite probable because I didn't tighten the screw that much
and watched carefully as I tighten it.

The second case,... I used Master Airscrew 11x6 and I'm not sure what "hub" you're talking about. Could u please specifiy ?
Thanks.
Jake.