OK, it’s definitely the commit with the null annotation refactoring.
Before trying to find the issue, I have reverted it on a branch made from the 4.0.0 tag, and made a JAR release.
Testers other than me, you are welcome to confirm if it works for you (do not forget to uninstall the binding from you runtime environment before installing the JAR in you addons folder).
EDIT : testers, see below for another jar to test
Now, as you said, it is not an easy task 
. I will try to pinpoint it but cannot give a date.
EDIT : see here for a real fix (no revert but also potential bugs)