iPhone XS Max Camera 'ghosting' issue? (lens glare/lens flare)

It's simple optics. You have a physically tiny lens that, by its very nature, is susceptible to flare (and other imperfections).

As far as comparison with SLRs is concerned, yes lens flare can happen under the right circumstances but, with a quality lens and a lens hood, it's not very likely. Many years ago, I took some pictures with deliberate lens flare that encircled a trapeze artist. In fact, I won some money in a contest with that shot.

yeah but this is happening without intention. and this is where the issue lies. If I wanted this effect I'd intentionally do so. Not every outdoor picture failing miserably because a green light or ring forms when I'm aiming ANYWHERE near the sun. Apple created what can be classified under their limited warranty as a "manufacturer's defect. This means you can take your phone in and they have to repair, reimburse, or replace the product. In fact, that's what I'm about to go do today.

Your previous cameras didn't have this sensor and lens assembly.

its not unique to the XS Max or iPhones.

It's lens flare, accept the definition or not, but that's what it is, or internal lens reflection if you prefer.

As far as a "smoothing effect," I certainly don't notice anything untoward in my photos.

You've "never ever" had this issue because no other phone or camera has the iPhone XS Max's lens assembly.

Here's another video showing it occurring.

Yes, it's basic camera physics involving a small sensor and limited lens size.

Samsung phones have similar issues.

None of your previous phones have the same lens assembly or sensor.

You can get lens flare on a DSLR with a $10,000 lens as well.

I have the same issue with my iPhone XS Max. It’s really annoying for $1200 iPhone. I don’t have same issue with non of my previous iphone

Good luck with that; optics not performing how you want them to are not a defect, and since they all work that way, that's yet more proof it's "as designed."

aiming ANYWHERE near the sun

I've had that happen regularly with a $5000 SLR.

You can make any lens flare, so "fault" is a harsh term for what is just a characteristic of optics.