Titans saw significant alterations. Characters drop in and out of focus, arcs aren't quite resolved, and there are a few moments that are confusing rather than effective.
Titans was subjected to extensive reshoots, which cut an original 13-episode first season down to just 11 episodes.
The story seems to have been compressed and refocused. The original season finale has been "cannibalized" to become the season 2 premiere.
• the reshoots led to an increased focus on Brenton Thwaites' Dick Grayson, strengthening his character arc and essentially making him the star of the show. This change in focus made Batman the main villain of Titans season 1.
• the Trigon plot, which was ostensibly the A-plot of the entire season, was compressed and ultimately left unresolved.
there's some evidence he was defeated in the original season finale.
• early episodes titled 'Starfire' and 'Rachel' were cut down into a single episode, 'Origins'.
• 'Asylum' was originally called 'Angela', suggesting a bigger focus on Raven's mother, which makes sense with an original focus more centered on Trigon.
• Beast Boy's seems to have been truncated; he's almost entirely absent from the first few episodes, there was an extended subplot building up to 'Doom Patrol', which was originally episode 5 but got moved forward.