Setting hibernate.hbm2ddl.auto to create-drop gets unit-tests stuck, setting it to update leads to errors

I am migration my Eclipse RCP application. In this process I switched from MySQL 5.0 to 5.9, from Postgres 8.4 to 9.4 and from hibernate 4.2.7 to 4.2.17 (because of this bug: http://ift.tt/1TvUDm1). The unit-tests are written (not by me) in a way that the database schemas get exported twice in the process of test-execution. Originally hibernate.hbm2ddl.auto was set to create-drop, which worked fine. Schemas were dropped and exported again.

With the new version of the application, when I use create-drop, the unit-tests get stuck at the exact test-case which tries to export the schema the second time. It's just stuck, nothing happens. Therefore I am now using update, which solves the problems of the unit-tests getting stuck, but some test-cases are failing because of that. (When I set the configuration of the old version of my program to update, I get the exact same errors in the unit-tests)

Is there any change that my Hibernate-version is incompatible to those DB-versions or any other error?

Very little information, but unfortunately I don't have a stack-trace, because the tests only get stuck...