Oil inside upper plenum?

I've been having an intermittent multiple misfire issue for the past few months. I was having the same issue a little over a year ago and discovered that the spark plug tube seal on bank one was allowing oil down inside the tubes, each one had about an inch of oil. At that time, I replaced the valve cover gaskets, spark plug tube seals and the upper plenum gasket. Car ran fine for about 6 months and then I started getting the misfire code again. If I clear it, it won't come back for a few days, sometimes a few weeks. I just checked the plugs on bank one, because that's the side getting the misfire codes and the spark plug tubes had about a half an inch of oil down inside of them again. Moreso, when I took the upper plenum off, there was oil between the upper and lower (see pics). The runners, however, seem to be dry. I found this extremely odd because when I replaced all the gaskets the first time about a year ago, I also deleted the PCV valves, there are just little air filters where the valves used to be now. I'm not sure how else the oil would get into the intake aside from a bad PCV valve but, again, I have none. Any insight would be appreciated. Thank you