In Publisher Subscriber model, is it fair for one subscriber to access the data changed by another subscriber

Question

In Publisher Subscriber model, is it fair for one subscriber to access the data changed by another subscriber

Let's say I have a publisher - Publisher1, and two subscribers - Subscriber1 and Subscriber2.

In this case, if Subscriber1 changes some data in the common data storage; is it fair for Subscriber2 to access that data.

Downside of it looks like, this might introduce a dependency, that Subscriber1 should be called before Subscriber2, and this does not look fair to me. But I am not sure though.