I have heard that the blotching seen on some side window glass under certain light conditions is normal and isn’t caused by flawed glass. Is this so?No! This phenomenon is commonly found in tinted and tempered window glass which is used in side windows and the blotching is caused by a heat treating process which varies from batch to batch and the tint appears blotchy when the light reflects off of it at certain angles. It seems to be more prominent in some cars then in others.
