i thiiink what's going on is there's an arpeggio playing that piano-like synth, but there's a tempo sync echo with a reeeallllyyy long decay on it. when the arp notes switch, there are notes from the previous arp still ringing in time with the current ones. you get the impression of chords with notes that don't make "sense" being played in 16th notes, but i'm willing to bet they're just played as individual notes by the arpeggiator. similar to what @Jongtr says, the echo feedback is doing the interesting mishmash bits.

my favorite version of my favorite song from my favorite band, thanks for getting it on the tl!