This un-syncing through the “phasing-out” technique was later pushed to its limits by modern composers such as Steve Reich (Piano Phase).
Video: www.youtube.com/watch?v=qKXy...

In Beethoven’s Sonata 13 (2nd movement, Scherzo), the un-syncing begins around 1:11, in the 2nd repetition of the 3rd section, when the right-hand line unexpectedly shifts forward by an ⅛ note. The idea is already ingeniously foreshadowed in the trio’s syncopation at 0:37.

Abbado died from cancer on January 2014 at the age of 80, around 3½ years after conducting Mahler’s 9th in Lucerne.
Mahler himself died 1911 about a year after completing that same Symphony.
Both seemed to sense death approaching—and sought to prepare for it.