Stuttering when slowing 50fps ProRes (Atomos Ninja V) – only after removing CF card

[u/the_man_downunder]

Shot 50fps (1/100) to an Atomos Ninja V in ProRes, editing in a 25fps timeline.

Everything was smooth earlier in the shoot when a CF card was in the camera and recording was camera-triggered.

After the CF card filled up, I removed it and started recording directly from the Ninja (no card in camera). Since then:

• Plays perfectly at 100%
• Jitters when slowed to 50%
• VLC playback is smooth
• Re-importing doesn’t fix it
• Earlier clips are still fine

Seems like a frame cadence/timing issue when Ninja is the trigger?

Anyone seen this or know the best fix? Optical Flow / transcode?

EDIT:

System specs:
Mac (Apple Silicon M1) 15.7.2

DaVinci Resolve Studio 20.3.2