I may just be an idiot but I cannot seem to figure out what I am doing wrong here. I assemble the fittings as instructed and can very very easily still pull the tube from the fitting. Here are some pictures.
This is the order in which i assemble the parts...

everything all tightened up...

can simply pull the tube out of the fitting...

I believe the instructions said not to overtighten the fittings, something like 1/4 turn after snug.