My upper radiator hose swells and pops off.

This started happening after I replaced intake, pcv, water pump, and associated seals and gaskets.

Coolant temp stays fine but the upper hose just swells and pops off every time I think I have the system bled properly.

The heat works fine... the lower hose and lower radiator get hot.. there is no coolant in the oil.

What could be causing this buildup?