Oiling pellets. Need opinions.

On the topic of oiling pellets, I don't do anything except just pull them out of the tin and fire them, but with the RWS ones I have it seems like they are dieseling. I've only recently started shooting a modern springer so I have to ask, is this common for certain brands of pellets?

As a side note, a PCP cannot diesel. The key concept our friend here is missing is that when you open the valve on one to fire it, you are equalizing the pressure on both sides while it's open, not compressing what is on the low pressure side of it.