When Uncle Jesse takes his cap off to mop his brow, he turns to see Rosco & his cap is suddenly back on his head afterwards.
When Luke Duke (Tom Wopat) is driving the red "slammer" car and using it to run the bad guys off the road, in the two close ups he is clearly driving the General Lee instead of the slammer car (presumably reusing stock shots from a previous episode).
44 minutes in you can see multiple cars on the smugglers transport truck even though when Bo and Luke took it from the hideout it only had 2 cars. One on top and the slammer on the bottom.
Obvious rigid-bodied dummies mounted inside the pale green car as it flips over --- the figures "sitting" in the front seats do not weave or wobble around with the tumbling motion of the car; they stay straight up and motionless at all times.
When Bo and Luke get caught snooping around the bad guys' secret set up, Bo (John Schneider) punches the first guy out. The man reacts to the punch too soon, grunting and falling back before Bo's fist can make contact and before the punching sound effect is heard.