Some small amount of play at the saddle is normal for this and every seatpost. It may increase slightly over time as the brass keys in the seatpost wear. Those keys are part of a refresh kit and should be replaced periodically during maintenence.

Excessive rotational play can usually be solved by addressing one of the following points:

Play between the seatpost head and stanchion tube

If the play is coming from the seatpost head and the stanchion tube does not show play, it is likely that your seatpost spring top cap is loose or the brass key which holds this assembly straight is damaged.

To check this:

1. Access the Top Cap under the seat clamp assembly by fully removing the seat and clamps using a T25 Tool
2. Remove the Top Cap with a 10mm Hex tool, and apply a small amount of medium strength thread locker to the threads on the cap
3. Tighten the 10mm hex bolt - use a torque wrench to tighten to 20Nm
4. Replace the clamp pieces and saddle
5. Tighten saddle clamp screw no tighter than 5Nm

You can see the Top Cap and how to assemble it in these instructions: TRS+ Seatpost Assembly Instructions

Play in the Stanchion

If the play is visible between the stanchion (the tube that slides up and down with the saddle) and the outer tube, this can mean the lower cable tower screws are loose or the mounting cap is loose.

To check the cap and screws:

1. Remove the seatpost from the bike
2. Remove the cable tower from the bottom of the seatpost using a 15mm wrench
3. Remove the mounting cap from the bottom of the post using a cassette lockring tool
4. Tighten all four T15 screws to 2Nm
5. Reinstall the cap and cable tower

You can find instructions on how to access these bolts in the first 4 steps of this guide: Seatpost Service - Disassembly