Have a niggling re: my MAP sensor, if anyone can throw some light on my situation!

Have the car serviced twice per year, every summer plus every winter. Only do 8-10 k per annum. Yes it might be overkill, however like things like that.

Now down to my question.

Every time my mechanic services the car he also removes and cleanes the M A P sensor, which is always chocked up every service. Its no big deal to remove and clean, Just one screw and a clip.

Just would like to know what's causing the build up. Why is this? Anyone?

Car is sport l494 4.4 diesel.

My last disco 3 2.7 did 285k miles before I sold it, and its still running and never had MAP sensor cleaned as far as time aware.

So Why does this one get blocked, clogged up? My mechanic can't answer himself.

Thanks in advance for any advice.

Kevin Rangerover Sport 2016 4.4 sdv8 A/B loire blue.