Dream Weaver was always a different recording. Gary Wright re-recorded it specifically for the film.
Apparently to restore Stairway, Paramount used a pre-theatrical mix with the OG Dream Weaver, so this replacement isn’t anything new necessarily
Why did this happen in the first place this just seems very odd.
Paramount likely used an element that happened to be the pre-release audio which not only had the original Stairway notes but also had the OG version of Dream Weaver so it was simply an oversight