Animation Camera/framerate problem

[Radace]

Hello,

Can someone tell me, why camera in my animation loose frames?
Moving objects in animation move in each frame when I scroll them manually, but camera move like 1 on 3 frames, (2 duplicated) and then frame move forward.

How to fix it? This problem makes all my animation like 33% smooth rest 66% frames are duplicated.
Camera is simple path from point to point in 50fps...