Hi Tarquin
I have occasionally had unexpected behaviours due to conflicting layout calls, and came up with the recipe here for hierarchy and order of calls some time ago https://therion.speleo.sk/wiki/bds#order_of_layout_functions_called
As far as I am aware, the last called layout or statement always wins. Certainly since I started using the recipe I have not noticed any problems, and my layouts occasionally have conflicting parameters for a particular setting (which is why I originally had problems – I was not rigorous about call order).
Seems to conflict with your experience, maybe mine are simpler?
(I don’t see an endlayout for your layout third – could that be something)
Bruce