Technically speaking they should indeed be separate. Space Paranoids is a copy of the Grid which makes kh2 Tron younger than DDD Rinzler and Sora meet Tron first
On top of that the world that the Grid resides in has fallen into the Realm of Sleep, at the very least, since before kh2.
Yet somehow Sora gets Rinzler to remember him at the end which has always irked/bothered me as well.
It's like copying any program or file actually. If the copies aren't synchronized either the copy or the original may be changed later on by someone (like Grid-Tron by CLU 2) but the other instance (Space Paranoids-Tron in Ansem the Wise's computer) will be unaffected.
Aren't you interpreting too much in there? The only thing Rinzler definitely remembers after Sora did something to his "heart" after their battle is that he actually is/was Tron once and that he fights for the users, that's why he suddenly takes CLU's blow for Sora, because Sora's a user. Reaching out with his hand for Sora is actually because he gets explicitly called "Tron" by him and remembers again who he truly is, he doesn't speak a word so if he specifically remembers
Sora as a person/individual is not confirmed (and unlikely, because it is not the same Tron).
The dialogue also does not indicate anything towards Rinzler remembering Sora himself, but only his true self/identity:
DDD said:
Sora: Tron!
(Sora reaches out to him and Rinzler tries to grab his hand, but is too
late and falls. CLU watches his descent)
CLU: I'll deal with you later. I have to retrieve Rinzler.
(Quorra walks over to Sora, who is still staring down the hole in the floor)
Sora: He reached for my hand.
(Quorra gives a sympathetic look)
Sora: Tron is still in there.
Quorra: You and that key have a special power.
Even Sora himself states nothing about "Tron remembered/recognized me" but only that Tron
remembered himself.
In overaching terms, this is another example showing off the powers of Sora's heart to connect with others which Quorra also points out.
The sheer fact that this Tron
isn't the Tron Sora knows and yet he still manages to connect with him and reach his heart to make him come to his senses actually displays Sora's heart connection powers with more emphasis than a similar scene with the Tron he already knows would have.
Or as Ansem the Wise puts it: "He has touched countless hearts, he has
accepted them, and he has saved them."
While the main focus and emphasis lie within the many original characters directly tied to him, mainly Roxas, Naminé, Xion and Ven as well as Terra and Aqua to an extent, Grid-Tron serves as an example to the "countless hearts" Ansem speaks of that Sora touches (advertently or inadvertently) and saves wherever he goes.
Is Space Paranoids even a copy of the Grid? From what I understand, Flynn pretty much created the Grid(and the game, Space Paranoids, which itself isnt in KH).
Anyway, yes, I was surprised 8 years ago. But it made sense. Also like that the Grid was included, but that may have been more impressive to have in KH3 in HD.
"Space Paranoids" is the name of the system and thus the name of the world inside the Hollow Bastion computer frame.
It was stated in both KH 2 and DDD that Ansem the Wise acquired a copy of the original ENCOM system (meaning the first Tron Movie, dunno how it was called there, certainly not "The Grid") and installed it on his own computer.
This means the "Tron" in the Hollow Bastion computer world is not the same as from the movie Tron but a copy. "The Grid" from DDD however is the original data world as was explained by Xemnas. Considering Rinzler exists, as well as CLU 2 and Quorra, in that world everything that encompasses Tron: Evolution, Legacy etc. happened as in Tron-Universe canon apparently.
However, the copy Ansem the Wise purchased from the original system remained unaffected by all of that and the "Tron" from Space Paranoids leads a different life than the "original" one in the actual ENCOM system which later becomes "The Grid" (or whatever Kevin Flynn actually did, I didn't watch the movie).
