I would like to see the fault codes pointing to the CAS, & why didn't he query the CAS module while the diagnostics were running? The CAS might be seeing symptoms from another module, like the LM module? There possibly be moisture issues in the headlights, causing the lighting modules to short due to moisture? Have you been seeing condensation in your headlights, & have you had any low voltage warnings on the dash? When you have strange electrical issues like this, always start with the battery voltage at the jump terminal. Turn the key on along with the headlights, with the engine off. Measure your battery voltage at the jump terminal to make sure it is above 12 volts. Anything less than this can causing strange electrical problems.