It seems there is an open issue with the very last Karaf version 4.2.0. Then we decided to upgrade to the version 4.1.0.
With Karaf 4 we can use also transaction-api feature provided by the container itself.
A big change from Karaf 3 to 4 is that the feature "wrap" is not a boot feature anymore,
Then, in feature definition we have to import it within hibernate feature and use `prerequisite = true` to handle the wrap protocol on bundle url.