Continuity mistake: The clasp on Raven's cloak also serves as an alert and tracking device, as we could see in "How Long Is Forever?" Robin, Starfire and Cyborg, whilst tracking Raven, find the clasp lying on a ledge in the sewer. But as they encounter Beast Boy as the super-werewolf and Raven hanging from his teeth, her cloak is still secured with the clasp.
Continuity mistake: When Silkie moults, he sprays the entire vicinity with his bodily residues, including the Titans. But after the regurgitated Johnny Rancid groans, "I got eaten," Raven is peachy-clean in the close-up when she murmurs, "So nasty", and right afterwards she is smudged again. And when Silkie and Starfire start gobbling up the residue, all the Titans are suddenly and fully cleaned up.
Continuity mistake: Robin calls up Cyborg as he makes his way to Steel City. When we see Cyborg on screen, the sky is daylight-blue and a bit cloudy. When Cyborg is seen personally, however, it is night outside - i.e. a dark clear sky full with stars; and when he activates the T-Car's hover function, it is still night, but the starry sky has suddenly become heavily clouded.
Plot hole: In Episode 2, "X" and Episode 5, "Haunted" we can see the mutant larva Silkie roaming around in the Titans' Tower. But Silkie is officially introduced to the series in episode 10, "Can I Keep Him?" - so how can he just appear in the TT's commando center without raising even one curious eyebrow to his thereto unexplained presence?
Continuity mistake: After the book starts talking, a startled Raven lets it drop onto the ground; the book lands so the viewers can see its spine. Following the commercial break, however, the scene switches sides, and the spine is pointing the opposite way from before so that the viewer can still see it. Correctly, the spine should be obscured from view and the page edges should be seen.
Continuity mistake: When the Titans enter the Tower ops room, only to find the mess Silkie has left behind, Raven's hood is down. As Robin comments on the damage, Raven steps up to the chewed-up sofa in the background with her hood up; but in the next shot, where she inspects the teeth marks on the sofa, her hood is down once again.
Continuity mistake: When Cyborg first comes into the H.I.V.E. eating hall, we can see several students sitting dispersed among the tables, among them See-More (the guy with the cyclopian helmet) and Kyd Wykkyd (the Batman-type kid). At first the two of them sit at separate tables; but when Cyborg sits down and Jinx, Gizmo and Mammoth confront him, we can see the two sitting shoulder by shoulder at the same table.
Continuity mistake: After first fighting Mad Mod's guard robots, the Titans are forced to flee when reinforcements arrive. One of the first two robots got damaged on the left side of its face, its left arm and shoulder, and its chest. As it turns into the alley after the Titans, the left face side is still torn up, but the rest of the damage has disappeared.
Continuity mistake: When the Titans land the T-Ship at the royal palace, the ground beneath it is bare and empty, but when Galfor brings Starfire and the Titans up to date on current events, the ground is suddenly teeming with parked Denthrax fighters. A giant fleet full of ships that had just attacked them would certainly tip the Titans off immediately, and if the Denthrax had cloaking technology, they would have used it against the Titans while they were still in space above Tamaran.
Other mistake: Cyborg/Stone attacks his own robot duplicate starting from near his fellow Titans, with his back turned to them. But after he has finished smashing it to pieces (thereby ruining his disguise), he suddenly is positioned so that he actually faces them, without having made any turn-arounds, since he charged his duplicate head-on.
Continuity mistake: Beast Boy snatches Starfire, yanks her into his quarters and multiple-locks the door. When the door closes, we see a number of locks, a door chain and even a door knob on the panel. In the first shot, the fasteners and bolt holes are positioned on the door frame and the locks on the panel; but as Beast Boy locks up, both locks and bolts AND the bolts fasteners are all located on the door panel, thus making the locks effectively useless. (I know that the locks are there just for laughs, but still the sudden location switch of the fasteners is undeniably evident).
Continuity mistake: When Beast Boy and Gizmo run into Cyborg's white blood cells, their positions before the side canal suddenly changes. At first Gizmo is at the left of the opening and Beast Boy to the right; but just before they run for it, Beast Boy is on the left and Gizmo is on the right.