For people having slow deflation problems, my Hammock V pad held pressure for a week (inside) but the Long Ultralight V I bought from this drop lost pressure overnight.
Below is at least one other person who mentioned that it could be the deflation valve leaking, and they showed a picture of an o-ring they put on it to seal it. I went to a hardware store and bought an assortment of o-rings (measure yours and take that info with you), and now both pads hold pressure for several days.
Not the best picture, but you can see where the black o-ring goes. It works for me, and it's inexpensive.