Perhaps try a different brand of sensor wipes and fluid. (Uh, I am not not trying to start a brand wars discussion, so I will just use the term different brand.)
Once upon a time a bug flew down my telescope and landed on the sensor and left a trail where it walked around that looked similar to what you are seeing. The trail only showed at certain f-stops. I could not get it cleaned off after using a lot of wipes and fluid. My local camera store person recommended trying a different brand. One pass with a dry swab (the usual approach for the new brand) and one pass with fluid and the mark was gone. I did use more pressure on the swabs than before.
If the mark is on the sensor or on the inside of the protective glass, it would have been there from the start. This will need a trip to the service center to fix, but it can be fixed.