[btilly]

There is no decoherence in MWI.

Yes there is. Decoherence provides the theoretical framework to explain why the superposition of parallel observers can never meaningfully interact with themselves again, even though a superposition of simple particles can.

See https://en.wikipedia.org/wiki/Quantum_decoherence#In_interpr... for more.

That said, the order in which an observer notices decoherence events has no particular physical importance.