Mystery of a Thousand Moons - S1-E18
Continuity mistake: In the previous episode, the Republic troops blasted huge holes into the Separatist lab to enter it. In this episode, in which the highly contagious airborne virus is unleashed into the facility, the holes are conveniently nowhere to be seen, so it can't get loose onto Naboo.
Continuity mistake: Rex's kama (the black kilt-like thing he wears) is missing twice: first when he, Anakin and Ahsoka are looking at a hologram of an AT-TE on the Resolute's bridge, and second when Anakin's trap for Grievous is revealed, and Rex orders the AT-TEs on the asteroids to fire. (00:01:12 - 00:04:10)
Continuity mistake: When the two factions of Hondo's pirates are fighting each other, the ones who sided with Maul and Savage are using blasters that fire red bolts, while the ones that stuck with Hondo shoot blue bolts. When Hondo persuades the traitors to work for him again and they attack the two Sith, all of the pirates' blasters are now firing blue bolts. This is Star Wars, not G.I. Joe, and weapons don't just change colour like that.
Continuity mistake: Besides Obi-Wan, Even Piell and Commander Cody, the exact number of people in Obi-Wan's group keeps changing.
Continuity mistake: After Grievous has received R3's message, he assures the dismembered R2 that he will not come to harm. We see R2's head lying on the dissection table with his electronic eye dangling from a cable. When Grievous stands up again, just before his MagnaGuards enter, R2 has his eye back in place. It's a brief shot, so you'll have to be quick to catch that glitch.
Continuity mistake: When Cad Bane is taken into custody by a clone trooper, the trooper changes from a shock trooper to a standard trooper between shots. (00:14:40)
Continuity mistake: After the droid advance force has split up to hunt down Master Yoda, the Jedi Master and his clone escorts attack each group on their own. When Yoda ambushes his group, it has six battle droids; but he is seen finishing only four of them. The remaining two just vanish from the scene. (00:10:10)
The General - S4-E8
Continuity mistake: When the 501st are pushing towards the Umbaran Airbase, most of the injured clones Kix drags away are missing their 501st markings, then in the next shot, they have the markings. (00:01:28)
Continuity mistake: During the end scene, when Echo and Fives are honored for their services, in the first shot, Echo's helmet is missing, despite his arm being positioned as if he's holding it. When his helmet appears, it's missing the red binocular attachment, which only appears later in the scene. (00:22:00)
Continuity mistake: The intro states Aurra Sing is presumed dead on Florrum by the Jedi, but the Aurebesh writing in the archives states she was 'last seen on Coruscant'. Impossible. Perhaps the archives are incomplete? (00:03:33)
Continuity mistake: For one shot near the start, the lightsabers on Ventress' belt are behind the buckle, but in all other scenes, they are hung in front of it. (00:03:56 - 00:04:38)
Continuity mistake: When Ahsoka leads a captive Cato to Jocasta and asks if she's all right, before they head off to call security, Ahsoka's lightsaber is absent from her belt in the first shot, but present in the second. (00:20:31)
Continuity mistake: When Obi-Wan Force-pushes the second droideka in the hyperdrive room, it rolls a considerable distance down the catwalk before striking an approaching squad of droids. However, in a following shot from below, the collision is much closer to where Obi-Wan was standing. (00:15:03)
Continuity mistake: When Plo Koon asks Matchstick about the damage to his Y-wing, Matchstick is wearing the standard Shadow Squadron helmet instead of his custom-painted one when he responds. (00:14:25)
Continuity mistake: When Rex pulls off the helmet of the disguised commando droid, Cody is missing the piece of armour protecting his right thigh. (00:09:37)
Continuity mistake: The opening scene after the narration shows the end of "Cargo of Doom" again, focusing on the clone troopers, but the details are different, including Anakin and Ahsoka disembarking the shuttle with R2 and some of the clones removing their helmets before leaving, when that didn't happen in the previous episode.
Continuity mistake: After the shuttle has crashed, there are four surviving clones accompanying Jar Jar. From the beginning of the fight with Turk Falso's group to when they escape out of the large geyser before it goes off, the number of clone troopers keeps fluctuating between four and three, before it stabilizes back to four when they go after the pirates. (00:10:34 - 00:12:03)
Continuity mistake: After Yoda cuts a hole in one of the droid battle vehicles, and throws the droid out, the following scene returns to Asajj and the Toydarian king. When their backs are shown, Asajj is standing close beside the king, but in the very next shot (showing them from the front), she is obviously a few feet farther from him. (00:17:08)
Continuity mistake: Satine and her guards along everyone else who entered the shuttle at the end of the episode disappear - you can easily see inside the shuttle and through the other window.
The Phantom Apprentice - S7-E10
Continuity mistake: Rex, escorting a captured Gar Saxon, is holding a pistol in his left hand when he stops because he sees where Ahsoka and Maul are fighting on the underside of the city dome. In the next shot, when he points at the fight and orders his men to get the gunships, he's holding a pistol in his right hand instead. (00:23:05)
Answer: Dooku never accepted Ventress as his apprentice, as far as I know; he just kept her as his devoted personal assassin. In Phantom Menace, it is stated that there can be only two Sith at a time, to prevent a power struggle in the lower ranks. To accept Ventress as an apprentice, Dooku would have violated that rule.