Bare with me, as these are just some guesses.
Would probably be incorrect to say they are there on the powder coated center area, you're just not looking close enough. If you say there's nothing seen, then it's duly noted.
I know that it's common knowledge that the CQuartz Coatings are susceptible to water spotting, usually in the coating's infancy, and why it appears the general consensus and practice was to apply a product on top such as Carpro Reload until full cure had been achieved.
I know it is said that DLX is applicable to metal, and chrome. I would suspect there is a difference of interaction of DLX upon different materials such as paints, or bare metals.
Could it be you possibly polished the lips beforehand, but did not get any-all residue carrier products off this area?
Have you tried to use, and have had any luck with the use of some sort of water spot remover? Or would you now say this water spot damage is permanent?
PS: Seen you made a similar post over at the other sister site.
Agree, worth mentioning, that I believe too that most modern wheels that have such a bare looking polished Aluminum Lip do have the entire wheel Clear Coated, so I'll assume there was no need to polish this area prior to coating. That such is not bare Aluminum.
That the likely cause could then be you didn't follow up with a protective sacrificial product on top of DLX. CP DLX may be unique in many respects but probably behaves similarly to CP CQuartz in regards to water spotting issues if certain precautionary additional steps aren't taken.