A guy at work put a magnaflow cat on his wife’s pilot and it did not fix the code. He had to remove it and install a “Honda” converter (whoever the actual manufacturer is).
Aftermarket cats are different than the oem units. The scrap value for an aftermarket cat is generally 5 to 10 bucks, whereas original to the vehicle converters are worth many times that (I think I paid him $80-$100 for the old Honda cat). I assume the lower scrap value for the aftermarket units are due to lower platinum, rhodium, etc content. My point is, a Magnaflow cat is not “the same thing” as what came on your Honda. I did put a Magnaflow cat on a 98 Dodge Ram I owned and had no issues (no engine light), though. So it’s hit or miss, apparently. I think I’d lean towards installing a Catco “oem equivalent” cat, if they make such a thing. The Magnaflows tend to be “high performance”, “free flowing” units. Which would concern me.