Many-world interpretation and absolute time

Consider a quantum system $S$ in superposition of two state,with an observer $A$, forming a bigger quantum system $S’$, with observer $B$. At $t=0$, observer $A$ measure $S$ and according to MWI, the world split into two possible world. Now at $t=t_{0}>0$, observer $B$ measure $S’$. Clearly $B$‘s result must agree with $A$‘s results. But form the perspective of $B$, the world split at $t=t_{0}$. So the time of spiting does not agree. Is that hinting absolute time does not exist in MWI?