I'm having the exact same issue for months now. Same codes. Would like to know what the issue is as well. What is your full exhaust setup? Also do you use a dp fix?
I've replaced front o2 sensors as well. Also reset lambda and AFR with no luck. Codes come back straight away.
BMW 135i N54 TWIN TURBO
Quarter Mile firstname.lastname@example.org - Street Tyres
Queensland Raceway Sprint 1:01:22 - Street Tyres
Queensland Raceway Clubman 1:04:74 - Street Tyres
Lakeside Raceway 1:03:97 - Street Tyres