Continuity mistake: When Tyrion is explaining where he has been and what he has been doing, he grabs a jug of wine by the neck. When the camera changes he now has it by the body of the jug. (00:07:30)
The Ghost of Harrenhal - S2-E5
Continuity mistake: Brienne and Lady Catelyn are with their horses by a stream talking. Brienne's white horse is walked into picture and is very dirty. The next shot the horse is clean. (00:38:40)
The Ghost of Harrenhal - S2-E5
Character mistake: When Renly and Catelyn are negotiating the terms of Renly's alliance with Robb, Renly calls Moat Cailin "Moat Caitlin." As someone who served as Master of Laws on King Robert's Small Council, he should know the correct name of the territory he is referring to.
The Old Gods and the New - S2-E6
Continuity mistake: When Maester Luwin walks towards Theon to try and talk him out of executing Ser Rodrik, he places his right hand on Theon's left shoulder. When the shot changes, his hand is no longer on Theon's shoulder.
The Prince of Winterfell - S2-E8
Continuity mistake: In the scene where Tyrion and Cersei are talking about sending Joffrey to the battlefield, Tyrion removes his cloth napkin from his shirt twice. (01:18:50)
Chosen answer: Considering the show was in production for nearly a decade, it is hardly surprising that many characters were recast. Actors constantly move on to other jobs, creating scheduling conflicts. Some may not want to be tied to one project for so long a period, particularly for relatively minor roles that paid little money. As some characters became more prominent, the producers did recast a few roles with better-known actors. For example, Max Von Sydow replaced the actor who originally played the Three-eyed Raven. Some actors voluntarily left for personal reasons. Jennifer Ehle was originally cast to play Catelyn Stark but dropped out because she'd recently given birth. Other actors claimed they were replaced for "political" reasons. Here is a website with a rundown of which actors were replaced and why: https://screenrant.com/game-thrones-characters-recast-new-actors-every-why/.
raywest ★