Thats correct. Most all sensors of this type do not do well receiving information when they are dirty or there is any obstruction. Frost like Ice crystals create optical phenomena, light reflecting off of the crystals in a process called scattering which can cause input information with these sensors on a MAZDA as well many other platforms. .I learned this when testing pilot license for my multi engine certification.

 

Heed p. 4-121 of owner's manual. It worked to get my 2019 cx5 automatic high beams to perform as advertised: The HBC operates to switch the headlights

automatically between high and low

beams after the ignition is switched ON

and the headlight switch is in the AUTO

and high beam position.

To get headlight switch into high beam position: push it forward and just leave it there.