Interesting -- my original (US non-rear fog) switch doesn't recess, but the replacement (Euro rear fog) switch recesses! I thought maybe received a defective switch until I read this. Everything works fine.
Maybe it depends on the part vendor???
E91 6MT Alpine, Terra, Xenons, ZSP, ZCW, ZPP, PDC, CA, alarm, M shifter and M brake handle, Euro rear fog light switch, Euro aspheric mirrors, rear power outlets, Garmin nüvi custom cupholder mount, Lidatek, V-1 built-in remote display, tire pump, jack, floor mats.