I have 3 of these, the older style ones and tehy give me NOTHING but good performance.
Whatever mode you should choose, they stay in. Sounds like you have them figured out how to operate them, so I won't bore you with that. I think it's time to have them serviced. Are they all on the same circuit? What are you hanging off them? I'm wondering if the voltage is weak(common problem) and is making them freak out? But it does sound like service time but I am concerned as you are saying more than one are all having the same issue.