I've been unable to demonstrate this. All my rules in one branch
always execute before the rules on the other branch (I have an AND
join joining these branches again).
I attached a simple example using an AND-split and two ruleset nodes,
where you will notice that rule 2 is executed before rule 1, because
they are both activated at the same time (in parallel) but the salience
of rule2 is higher, so it is executed first.
Kris