Fat Albert's shirt was clearly fading before the scene where he's hanging outside the window trying to get Lauri's attention. However, when he's at the window, his shirt is bright red again. It returns to being faded when he lands on the garbage bags.
When Fat Albert meets Bill Cosby, you see Fat Albert raise his right hand to shake Cosby's in a shot viewed from behind Fat Albert. The next shot shows a view from Fat Albert's front, and he once again raises his hand to shake, even though he never put it down.
When Fat Albert opens the door for Lauri as they get into the car on the way to the dance, the right front metal gate "door" hinges at the front and Lauri steps behind it to get in the right front seat. In the next shot, Fat Albert closes the door, and the door is now hinged at the rear.