The Barbarian Sublimation - S2-E3
Continuity mistake: When Penny explains she has bought the game, her grip on the laptop changes. (00:06:50)
The Barbarian Sublimation - S2-E3
Continuity mistake: At the start, after Penny has dropped one bag, there is an item in the top of the remaining bag. This item keeps appearing and disappearing. (00:01:20)
Continuity mistake: When Leslie and Leonard are talking about starting a relationship again, the can of Diet Cola keeps rotating. In some shots from Leslie's point of view you can't see the logo and in others you can. (00:06:30)
Continuity mistake: When Leonard says he is happy Penny is moving on he has nothing in his hand. Camera cuts and now he is holding a bit of bread. (00:03:00)
Continuity mistake: When Sheldon is undoing a pair of socks that Penny has paired, Penny is seen holding a single sock. Camera changes and she now has nothing in her hands. This is an instant cut. No time to drop it. (00:05:50)
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 Escape Hatch Identification - S10-E18
Continuity mistake: Stewart eats a ham sandwich when he and Raj are talking alone in Howard's and Bernadette's living room. On at least one occasion the sandwich's size gets larger, not smaller between bites as Stewart is eating it.
The Ornithophobia Diffusion - S5-E9
Continuity mistake: When Leonard and Penny are at the movie theater the same couple walks behind Leonard, twice.
The Fetal Kick Catalyst - S10-E6
Continuity mistake: Near the end of the episode where Sheldon and Stuart are drunk and talking about how Sheldon never leaves the house without a paperclip, the amount of Mimosa in their glasses suddenly decreases between shots.
The Brain Bowl Incubation - S10-E8
Continuity mistake: When Raj puts down the rubber gloves when talking with Isabella, the gloves completely vanish 6 shots later with nobody touching them.
The Dependence Transcendence - S10-E3
Continuity mistake: Bernadette is talking to Raj's dad on the video phone. In the close up, her fingers are wrapped round the phone but in the long shot, she is holding her fingers behind it and balancing it with her thumb.
The Financial Permeability - S2-E14
Continuity mistake: Sheldon opens the can with money in and puts the lid on the side, However in some shots he has the lid in his hand. (00:04:00)
The Financial Permeability - S2-E14
Continuity mistake: When Sheldon is holding the money out to Penny, the can that is being held by Sheldon is constantly moving up and down in height in relation to his shirt. (00:04:00)
The Killer Robot Instability - S2-E12
Continuity mistake: When Penny and Howard are arguing near the start, Penny has her arms crossed in one shot and down by her side in the next. (00:04:50)
The Panty Piñata Polarization - S2-E7
Continuity mistake: At the start when Howard is asking about the house, the pencil in front of him keeps moving on the table. Note the point and the edge of the table. (00:02:30)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: When Ramona starts talking to Sheldon in the cafeteria, the way Sheldon holds his knife and fork changes between shots. (00:04:00)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: The way Ramona holds her drink in the cafeteria changes between shots. (00:03:50)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: At the start as Leonard says about being able to talk to women, he puts his hand on his drink. Camera cuts and now his hand is back by the edge of the table. (00:02:50)
The Bat Jar Conjecture - S1-E13
Continuity mistake: When Raj is talking about psychological warfare he has a fork in his hand in one shot and not in the next. (00:08:40)
The Hamburger Postulate - S1-E5
Continuity mistake: When Sheldon is ranting about his board being changed, there is one shot where his hand is uncovered then covered by the blanket. (00:12:00)
Answer: Because Raj's selective mutism seems to be caused by women that Raj sees (on some sort of conscious or subconscious level) as a potential sexual partner. An attribute that wouldn't apply to either his sister or mother.