I Can't Believe It's Butter - S10-E13
Revealing mistake: When Griff drinks the gravy right before calling "Butter", his glass is empty.
Guess Who's Coming to Breakfast, Lunch and Dinner - S10-E1
Revealing mistake: Near the beginning when Al is looking for his magazines under Bud's bed, a large shadow of someone crosses over him showing someone in production crossed in front of the lighting.
The Hood, the Bud and the Kelly (2) - S10-E15
Revealing mistake: Whenever Al or Jefferson falls off the roof you can plainly see it's a dummy wearing their outfits.
Revealing mistake: When they blow up the scoreboard at first in slow motion, the entire scoreboard is blown up and destroyed. The next shot only a small portion at the top and middle is destroyed, not the entire thing.
Answer: It's implied that Steve filed for divorce since in s04e16, "You Gotta Know When to Hold 'Em", Marcy says that Steve is suing for alimony. Alimony is something that has to be requested when filing for divorce. Although the show doesn't spend time on the actual legal proceedings of their divorce.
Bishop73