[TBG]

I have an M4 Competition from 2021 with an R44 exhaust, both with OPF delete and catless downpipes. An incredible exhaust.
My car is not tuned, and I use the well-known OPF delete cables and CAN Mill Deleter from Leib.
This works well, but sometimes a yellow Check Engine Light icon appears on the dashboard. It doesn’t go away.
I’ve discovered that this only happens when I let my car idle for a few minutes.
I’ve never had a warning while driving. Through the Bimmerlink app, I see a warning related to my catalytic converter and OPF. My conclusion is that the CAN Mill Deleter only fails in neutral after some time, but not while driving. But that doesn't sound logical. Anyone have an idea?

Codes:
1A2810
180001
180101