Continuity mistake: In one scene on the planet, Riker's clone is lying under a table fixing something and Riker is sitting in a chair talking to him. There are two camera angles used. In one angle when the clone is talking and a body double is sitting in the chair he is facing directly towards the table but in the other camera angle where you can only see Riker, the chair is at an angle facing towards where his clone is lying on the floor.
Continuity mistake: William Riker is playing cards with La Forge and Worf. The camera is focusing on Riker and there is no 4th chair. When Tom Riker enters, William says "Why don't you join us" and now removes his trombone from the 4th chair which has suddenly appeared. (00:31:25)