The Great Petrie Fortune - S5-E6
Plot hole: If Rob was just 12 or 13 when he last saw his grandfather (that's what they said in this episode, also he never called his grandfather ever from what it looks like) then his grandfather wouldn't know that he has been working on a TV program. (He started working on the Alan Brady show when he was 20, not before).
Suggested correction: First of all, it is Rob's great-uncle, not his grandfather. And what makes you think he wouldn't know? Off the top of my head, I can think of a dozen ways he could have known. He was watching the show and saw Rob's name in the credits. His brother called him to brag about his grandson. He read a magazine article about television comedy writers. Etc. Etc.
The Great Petrie Fortune - S5-E6
Factual error: Rob tells this lady that the guy that passed away was his great-uncle and that the last time he saw him was when Rob was 12 years old... This is the same Grandpa that was also seen in the episode "What's in a Middle Name" (in this episode in season 5 Richie would be 10 or 11. But the other episode he was supposedly 8).
Suggested correction: You seem to be confused about Hezekiah's relationship to Rob. He is Rob's great-uncle which means he's the brother of Rob's grandfather, the character from "What's in a Middle Name?" (And by the way, the scene in that episode took place before Richie was even born. The fact that they were arguing over his name should have been a clue).
The Great Petrie Fortune - S5-E6
Revealing mistake: The great-grandfather Petrie was just Rob Petrie dressed as a really old man. The lamp in the movie is also one that has been in Robs house and Sally's house in a few of the episodes.
