Because this bug is so important for us I came up with a patch for hib 4.3.6.
I created a few minimal test projects that illustrate how things used to work under 4.2.x, how they originally did not work under 4.3.x, and how the patch fixed these issues.
The advantage of these tests is that you don't need wildfly to run them, just maven and mysql (should be easy to switch to another database).
As I'm not an hibernate expert, and hardly know what the new 'load plans' are, there is a fair chance that my patch is far from perfect.
I just checked that our application works correctly with the patched hibernate, and believe this patch might put the true experts on the correct track to finally fix the problem.
Please let me know how to proceed ...

Hi,

May thanks for having a look into this issue and developing a patch! If you haven't done so, you should create a pull request on GitHub (https://github.com/hibernate/hibernate-orm/). One of the ORM devs will then take a look at it.

Thanks again,

--Gunnar

There are a few practical problems with that:
1) I'm used to developing with subversion and maven, a switch to git/gradle is a bit challenging to me (it will take too much time to get things going)
2) I already invested a few days of my company's time in fixing these bugs, so practically speaking there is no time left to investigate new technologies
3) I'm going on a 3 week Holiday tomorrow evening.
I'm willing to send a zip file with the patches, related test cases, and a bit of documentation to someone who's interested in my solution.
If that person already knows a bit about git/gradle/hibernate that would be ideal...

As explained on https://forum.hibernate.org/viewtopic.php?f=1&t=1035834 our core problems will likely be fixed in the next release of hibernate 4.3.x.
We're essentially waiting for a release containing the 18/8 fix of the problem, and hope it will arrive soon ...