A slow resetting trigger or on-off is a normal symptom of bolt stick. The on-off not resetting, is an indication that there is not enough stick to prevent firing, but there is still too much stick to allow a proper reset.
A leaking on-off oring could cause problems as well, but most of the time it is the carrier size. If the next larger carrier size causes a leak, try a new oring in the carrier and go through the tuning process again. Sometimes, you just get an oring that has a flaw that allows a tiny leak under normal circumstances, and causes you to use a carrier size that is too tight to prevent that leak. Always remember to tune without any powertube shims installed. You don't need them, and they can cause leaks that will make you use a carrier that is too tight.
Except for the Automag in front, its usually the man behind the equipment that counts.