Yes that is most likely what is happening and it’s why I don’t hit my quads unless it’s very high. If I hit the outer middle- I often clip a nerve with the oil and after I pull out I already know I’m gonna get a knot. You will know when you get an infection. Knots are common in this game but infections are rare.Palumbo has repeatedly stated he's against quad injections due to the large amount of nerves in the quads, it has nothing to do with infection risk.
I guarantee headtrainer isn't getting infections repeatedly in his quads, he just doesn't know as much as he thinks he does - as you said, he clearly doesn't realize that knots don't equate to an infection.
It's very rare that I address people directly but this is deserved, headtrainer has posted too much bad info in his time here.