My issues are more often "fender" than B pillar, but they too are nearly always on the left. My armchair theory on this is it's affected by spray etc passing lorries, often very close on motorways. Maybe just what all that looks like to a camera, the cameras themselves are generally clean.
I did have a faulty camera replaced but I'm still getting the error and it's pretty much always on the left, albeit on some journeys all is fine.
I was thinking the same - spray, mist..... but my issues so far mainly b-pillar cameras. Is the fender a completely sealed unit? Does it have any means of clearing internal fogging?
Not surprisingly, a bunch of the messages I get make sense. IE They appear when the sun is shining (low) and either directly at or across the camera window. The first time I noticed this it happened to be the right b-pillar, and of course I then convinced myself that it was always the right side. Sometimes got the message 'AP suspended for remainder of trip' after prolonged 'blinding' (probably the front camera) but message cleared on its own and AP reactivated itself - several times.
But I kept getting the feeling that the b-pillar messages did not always link to obvious issue such as sun, fogging glass, spray.
Last night, driving along clear dry lanes and small roads in the dark of night, the message popped up for Left b-pillar being blinded. I wasn't using ap at the time. My car was spotless and I had been driving for an hour already with no issue. The message stayed on the IC display for may be a minute or two during which time I could see no common external common factor. The only think is that it was quite cool outside, in the 1-5 degree C range.
Here is my current take on the issue / problem. With no ac on, (even with recirc off) cars (and especially EV's apparently) tend to mist up inside. My guess is that's due to reduced permanent airflow through cabin designed to help keep temperature comfortable without excessive heating. So cabin humidity tends to be higher than we are used to with ICE cars, and in cold weather we keep the windows closed more.
When windows mist, you turn on heater which clears the windows OK, but does not reduce humidity. In fact, it quite possibly increases humidity. If the warm cabin air can heat glass surfaces, then that will reduce formation of mist / condensation on glass. However, the b-pillar cameras are exposed to (probably humid) cabin air, but without any significant flow of warm air to warm the b-pillar glass. On the outside of the car is obviously a steady flow of cooling air, especially if the outside of glass is wet and evaporating, which will cool the glass quite a lot. So cold glass with humid air on the inside is bound to form condensation on inner surface with little way of removing it other than???? more cabin heat? which is likely to increase cabin humidity while doing litte to ventilate or warm the b-pillar glass. Simple answer is a small fan in the b-pillar to keep air moving and help evaporate the condensation.
So I reckon my problem with left camera last night was no more than outside temperature dropping, b-pillar glass cooling, fine condensation forming inside b-pillar glass, one car behind and a few street lights were enough to 'illuminate' the fogged glass, and the car displayed its normal 'blinded' message until it was happy again.