When Chloe walks into the toilet, you can clearly see that the time shown on her watch is around 08:45 while the time is 09:38.
Agent Richards is back to his job of inflicting pain, but his first name seems to have changed from Darren to Eric in the credits.
In S04E02 when the blue Lexus drives through the gate at the train station parking lot exit, the car breaks the gate arm which falls down. In S04E03 in the 'Previously on 24' section in the same shot, the piece of arm falls down to a different place, which means different shots were used in the two scenes.
Also in the 'Previously on 24' section, when Jack goes though the same gate, the fallen piece is disappeared.
Also in the 'Previously on 24' section, when Jack goes though the same gate, the fallen piece is disappeared.
During the "Previously" clip, Navi talks to Behrooz, stating that Omar saw him with Debbie outside the compound. But during the original episode, he stated that one of Omar's men saw him outside the compound with a girl, not Omar himself.