2011 X5 50i oxygen sensor question

[Zaner]

I recently purchased my 2011 BMW X5 50i with 153,000 mi on the clock. It was well maintained with $16,000 worth of receipts from the local BMW dealership in the last year and a half.. it looks great it runs great. But for some reason everyday, I get a check engine light with two reoccurring codes 2c2d and 2c2e. I see where about a year ago the oxygen sensors were changed out by the dealership and then trying to do the easy thing and fire the parts Cannon, I swapped them out for some Bosch oxygen sensors. Surprise no change in the reoccurring codes. I apologize if my question is redundant and has been asked before. I searched quite a bit before coming here..I've never owned a BMW before and all my past automotive experiences has been with ls powered vehicles. Interested in hanging around and learning more about these cars. Any idea of what I could looking to next that could be the likely a culprit, that's causing these oxygen sensor codes? Thanks in advance