Yep it is the trigger. Factory recomends cleaning trigger with electrical connector cleaner(will not leave a residue). I believe this is similar to brake cleaner, but not sure. Spray it in there heavy, then I use a can of compressed air to spray it out. Factory recomends not to oil at all after cleaning. It is the oil that collects the dust, and the residue. I actually have two spare triggers. Remember the Knight has the best trigger, but it does need TLC. I would sell them both for $75 shipped, if anybody wants them. Tom.
I do not know why the picture did not come up. I can e-mail one if someone wants to see them.