The Recollection Dissipation - S10-E20
Continuity mistake: When Howard and Bernadette are talking in the kitchen by themselves, Howard's bottle of water keeps moving between shots.
The Long Distance Dissonance - S10-E24
Continuity mistake: After the 'Ramona' conversation between Sheldon and Penny ends, Sheldon leaves Penny alone on the couch. Penny looks up to the "Amy and Penny" painting and says "Don't look at me like that, I tried." In S10 E10, Amy gave the painting back to Penny, which was hung in Leonard's living room.
The Long Distance Dissonance - S10-E24
Continuity mistake: When Sheldon takes a plane to see Amy in Princeton, the plane he is on has 2 engines when it takes off and 4 engines when it lands. It's a direct flight from LAX so he wouldn't have changed planes.
The Proposal Proposal - S11-E1
Continuity mistake: When Penny and Bernadette are talking in the kitchen, the string for the teabag in Bernadette's yellow mug keeps moving between shots.
The Retraction Reaction - S11-E2
Continuity mistake: Sheldon's formulae are written on three whiteboards. The marker color on the leftmost board is first red, later black. (00:07:05 - 00:09:21)
The Retraction Reaction - S11-E2
Character mistake: When speaking on the radio, Leonard says he has never heard himself through headphones. We have seen him several time wearing headphones while speaking, for example during a podcast with Will Wheaten and on Science Friday too.
The Retraction Reaction - S11-E2
Deliberate mistake: Leonard is on NPR on a Friday, and the guys don't talk about it until the following Monday at work. They spend so much time together, they surely would've discussed it sooner.
The Retraction Reaction - S11-E2
Character mistake: When Leonard arrives at the Human Resources office, he tells the HR person that he's not used to being called into the Dean's office. He's not in the Dean's office, he's in HR.
The Relaxation Integration - S11-E3
Character mistake: When Sheldon is telling Leonard, Amy and Penny about how his voice is like a white James Earl Jones, he quotes the famous Darth Vader line "Luke, I am your father." This is an example of the Mandela Effect, that apparently even Sheldon Cooper is susceptible to. Darth Vader actually says "No. I am your father."
The Proton Regeneration - S11-E6
Character mistake: While bedridden after his vasectomy, Howard asks Bernadette to grill up a couple steaks instead of picking up Chinese for dinner. She gives him a disapproving look and he says "Kung Pao Chicken, please." A major ingredient of Kung Pao Chicken is peanuts. A major allergy for Howard is peanuts. (00:09:04)
Suggested correction: Since they are both quite well aware of it, they likely have either found a Chinese restaurant that doesn't use them, or they get it without peanuts.
Yup. My friend is allergic to peanuts and our local Chinese restaurant makes hers with almond instead of peanut.
The Bow Tie Asymmetry - S11-E24
Continuity mistake: After the ceremony, as Amy and Sheldon are walking down the aisle, different camera angles show Barry Kripke holding the microphone in different hands but without changing them as he is singing.
The Imitation Perturbation - S12-E6
Continuity mistake: When Bernadette and Amy are sitting in the kitchen, the teabag in Bernadette's cup changes position between shots.
The Consummation Deviation - S12-E8
Continuity mistake: Leonard tells Raj that the first sex between Penny and Leonard was fantastic. But episode S3E2 is all about how bad it was.