[Sequencer] Every nth frame is still

When rendering an output with Sequencer, my level sequence is set to 60FPS, and rendering out at 60FPS, I have ‘Always Tick Pose and Refresh Bones’, however when reviewing the rendered frames, every 2nd sometimes 3rd frame is a still, and not the next frame of animation - in editor, the frames are consistent and animation plays fluidly.

This happens with all render formats (avi, png, etc…)

hi, i have the same error issue now in the 4.15.2 , you find the solution? thanks in advance!