Images in sequence too slow at first time ir plays

1

Hello

I have an animation in 3d, exported in frames, 200 frames total.

Have imported all at the timeline, in sequence. the problem I’m having is that when I play the movie the first time, the animation of the frames plays too slow, slower than the original frame rate of the frames. At the replay, the movie plays OK, at normal speed. How can I prevent that?

thanks