Vector 3 Calibration inconstant

Hello,

There is a strange behavior of my Vector 3 pedals.

I've mounted the pedals on a stationary trainer (Kettler Racer S). If I start training doing a static calibration. Mostly the showed Watts are up to 20 lower than the trainer shows. After pedaling about a minute doing the calibration again. Then the values of trainer and pedals matches well.

I installed the pedals with a torque wrench (35Nm).

Could anyone else notice this?

Greetings Thomas