Apparently, a professor taught the regular version of general chemistry to a class of students enrolled in the remedial/introductory version of the course. KHOU I-Team investigates!
My theory: Nguyen taught the correct class. The students found it too hard. Straight-A Snowflake complained to the science chair, who realized that the pass rates in the class were going to be abysmal. Science chair had a little chat with instructor Nguyen, who realized what she needed to do if she wanted to get rehired the following semester.