If two members both with their own persistent store (BDB) are started in order A, B, then B will overwrite its data with A's since A is the coordinator -- even if B's data is fresher than A's.
JbossCache does not keep track of the age of nodes?
No, it doesn't. It's up to the user to restart a cluster with unshared CacheLoaders in the correct order (latest changes first).
However, you could also merge the data yourself (e.g. with a DB), and then the startup order doesn't matter