The Rhinitis Revelation - S5-E6
Other mistake: When Mary is rubbing VapoRub on Sheldon's chest, she makes a comment that last time she saw that there was no hair, to which Sheldon replies "Yeah it filled in last year." In Season 1, Episode 11, Penny rubs VapoRub on Sheldon's chest and a very clear remark about chest hair was made. Season 1 for the show was 4 years ago.
The Countdown Reflection - S5-E24
Other mistake: Raj doesn't get over his selective mutism until the end of season 6. However, he very prominently speaks during Howard and Bernadette's wedding without alcohol or meds. In the season 6 episode where he finally does speak without any assistance, Penny makes a big deal about it so it's shocking when he does it here with no big shocks.
Suggested correction: Sheldon is probably joking when he tells Mary his chest hair filled in the previous year.
Sheldon doesn't make jokes.
Ssiscool ★
He doesn't understand sarcasm, hence, doesn't know when to be sarcastic.
ckbyers
If Sheldon didn't make jokes, the term "Bazinga" would have never came into play. Ever.
ckbyers
And nearly all instances of Bazinga are not used in a funny circumstance. Indicating poor judgement and lack of knowledge regarding jokes.
Ssiscool ★
They were funny to him. And to the audience.
lionhead
Google "how many times has Sheldon said "Bazinga" " - and it'll explain that he does, indeed - joke.
ckbyers