JRebel extension currently does not pick up changes in datasets.
Here is how it works:
If there is no target/jrebel-temp/.../*.meta file for given deployment then it assumes user wants full redeploy. If such file is present then deployment is blocked and tests are run at once.

JRebel extension also checks if there is a rebel.xml file in the archive. If not then it generates such file based on exact content of the archive and explodes archive into target/jrebel-temp/*.

Now the problem is that if resource is not in the archive then it will not be included in generated rebel.xml and thus won't be picked up by JRebel.
Datasets are now automatically packed inside WEB-INF/lib/randomUUID.jar. JRebel will not substitute resources or classes from bundled libs. We could generate additional rebel.xml for that but I'd have to know what is the name of such archive and we would tightly couple both extensions.

It would be easiest if Persistence ext would pack datasets directly into WE-INF/classes.