I found a Brother website that clearly stated do not oil the machine (my model, basic mechanical.)

mine too. works every time

did you run over a pin lately may be there is a small piece down by the bobbin

I don't think the "no oil" instruction includes oiling the wick associated with the bobbin. Whether a new machine or old machine, if it has a wick associated with the bobbin race, that wick should be oiled so it does not dry out.

Always check the manual or ask a knowledgeable dealer if you are unsure to oil or not. A good dealer will tell you and not say you need to bring it in to our shop.