This is just a pure guess, cause I have never touched that part directly, but maybe this would be a hint. This transaction error seems like a common message also for situations, when you try to carry out an operation that would clearly violate database rules, for example reinsert the same value for a primary key or a unique key. Now, looking at your example, this could be happening (knowing that publication should always create a new version)... I would inspect all the operations to see what is happening, and compare that to the db table state...
