P1132 and P1152 OBD2 Codes on 2001 Ford F150 5.4L V8 - Possible Causes After Oil System Flush and Maintenance

I own a 2001 Ford F150 with a 5.4L V8 2WD engine. Recently, I've started receiving OBD2 diagnostic codes P1132 and P1152, which indicate issues with the oxygen sensors—specifically, a rich exhaust condition detected by the HO2S (Heated Oxygen Sensor). My programmer suggests this is due to an overly rich fuel mixture. I performed several maintenance tasks today right before the check engine light came on: I completed a 5-minute crankcase oil flush, changed the oil from Mobil to Royal Purple, added an oil restorer to improve engine compression and horsepower, replaced the oil filter from Fram to Wix, cleaned the MAF sensor with dedicated cleaner, and thoroughly cleaned the throttle body. All of these were done during my drive to O'Reilly's to drop off the old oil. Shortly after completing these tasks, the check engine light activated, and upon checking with my programmer, both P1132 and P115-2 codes appeared. This is concerning because I didn't notice any noticeable performance issues or fuel smell. The truck has 69,500 miles on it. I've previously replaced the manifolds with short-tube headers and installed a 40-series exhaust system in place of the factory muffler. Additionally, I swapped out the throttle body for a BBK unit several years ago, and replaced the MAF sensor with a GMS unit; my air intake is currently equipped with a K&N FIPK II kit. Given that all these modifications were recently completed, could any of them—especially the oil flush or the new oil additives—be contributing to the oxygen sensor readings? Or is this simply a false positive due to transient engine conditions? Any insights from experienced F150 owners or mechanics would be greatly appreciated.