I have this exact same type of dust caps, but never had this issue. I normally check air when I pump gas, so may be it helps to keep them loose. But anyway thanks for the info.
There's another thing. When you let the workers at sheds to check air, they tend to tighten these dust caps to their maximum, like they prevent air from leaking.
So normally I do the dust cap tightening part myself whenever there is a worker to help.