I read the article on desynchronization and I understand why I am shot behind walls; however, it also states that it favors the shooter and simulates locally which begets my question-why do I have lag on my shot registration tick marks?
If someone could assist me in my quandary, I would be appreciative.
The unprofessionally crafted netcode in Infinite is the source of all desync. It wasn’t play tested either and was really rushed leading to the absolute mess that it currently is. There’s nothing players can do about it, we can only wait for the engine to be overhauled in its entirety.
Ask 20 people you’ll get a spectrum of similar but differing answers, desync is a really catchall buzzword of various underlying issues ranging from latency to misunderstood underlying mechanics to communication between optimizations and platforms.
From a lot of descriptions and evidence of it I’d lean heavily in the direction of server side communication between players of differing latencies as the main issue. Platform optimization and communication on a crossplatform basis is speculated quite often, but there’s been no concrete evidence to support these claims not just on Infinite, but the plethora of other titles that players purport this as well.
This is where latency comes into play. If you have high ping or other players have high ping), it takes longer for the local simulation to reach the server to verify the actions and interactions that were taken. If the ping difference is great enough, this can manifest in shots “curving/penetrating” around/through walls or hit-registry errors due to targets and shot placement not lining up logically when compared server side.
While some of what you say is a contributing factor, that’s not what OP was asking
I don’t think anyone really could have said it better than how Trand0 just did.
Whatever the reasons are, this game is the absolute worst out of any game I have ever played. When it works it feels awesome but the majority of the time I play it simply doesn’t feel good at all.
Here is a good video on Desync info in Halo Infinite!
https://www.youtube.com/results?search_query=what+is+desync+in+halo+
Peace! 
