[Siren_G]

Are people getting these with decatted downpipes?
I've got all 4 codes 2c9c, 2c9d, 2c9e, 2c9f. We're there when downpipes were first fitted.
Eml doesn't come on as jb4 auto clears it. All 4 02 sensors just replaced and the code continues when reading off the jb4 interface. Question for those with downpipes, should I be concerned? Burger tuning says it is a lambda fault so I M perplexed. Fault codes were cleared etc and it still comes back. Do I need to get the thresholds raised?