first step: create a test case in your app reproducing the issue - that could be of some interest to us anyway

Done - this is how I diagnosed this issue

then try to reduce to the minimum the test case, still in your app

Tall order - there is a lot of code and thus quite an effort to pair it down - might be that I pair it down too much....

then with the test case template set up to use PostgreSQL, try to migrate the test case here

Might take some time - though you have given me an idea - I have not checked if this issue occurs with HSQL (our test unit database). Might be easier to set -up such a test case and see. Although, even if it succeeds we cannot really infer that it is a PostgreSQL related behavior....