Sequencer keyframe interpolation not availible

I made a BP construction set animation in sequencer.
It works but I cant change the keyframe interpolation - its always constant.
The Keyframes are white so I think its an other type of Keyframe.

How can I change these Keyframes to “normal” so I have access to all Interpolation Settings?

EDIT / Closed:
Integer Variables cant be animated in all Keyframe Interpolation modes. Scalar variable can be animated normaly and switched to Integer afterwards in BP