P2096 Diagnostic Code on 2012 VW MK6 GTI with APR TurboBack Exhaust and No Catalytic Converter

I recently installed an APR TurboBack exhaust system on my 2012 Volkswagen MK6 GTI, which does not include a catalytic converter. Using the APR mobile app connected to my vehicle's OBD2 port, I've detected a P2096 code indicating 'Catalyst Fuel Trim System Too Lean Bank 1'. There is no check engine light illuminated on the dashboard, and I haven't noticed any unusual noises or performance issues beyond slower acceleration compared to before. The car has been tuned with a Stage 2 tune paired with the TurboBack exhaust setup. I typically run it on 93 octane fuel, but after the P2096 code appeared, I switched to 91 octane for a short period—now I've reverted back to using 93 octane. Despite no visible warning lights or dramatic symptoms, the code persists. What steps can I take to resolve this issue without triggering engine damage or performance loss? Any insights on whether the absence of a catalytic converter affects P2096 detection would be greatly appreciated.