A couple of times when we got off the highway and came to a stop the door would swing open all the way.
I own an 1980 Boler
13ft and do not know too much about the triliums.
I am sure that is how the crack came about and by no means strucural and can be fixe cosmeticly.
I know that RV dealers sell some sort of tie so doors will not swing open but as a previous owner had installed a hasp with a small pad lock this is what I use.
The hinges on my Boler look original but I am sure that again a previous own put in bolts with nuts and peaned over the tread so it would be locked instead of wood screws
The nut is hidden compleatly by the doors weather striping.