Hi, The only thing that would blow the hose off, is a back fire into the inlet manifold. Not a common thing with modern engines. About the only way it could happen, would be if it was very lean at that time. The mixture burns slower when very lean, so that when the inlet valve opens, the still burning mixture ignites the fuel in the manifold, to fire back into the manifold.
Don't know why its lean, could have something to do with the hard starting, when hot.
Harvey.
