Playback problems Macbook USB-C via BM Ultrastudio recorder 3G


I’m trying to input my camerafeed (Sony PXW-FS5) via a Blackmagic ultrastudio recorder 3G (thunderbolt 3) into mimoLive. I did all the installs and have a powerfull mbpro 2018.

The Problem:
MimoLive recognizes the blackmagic recorder and shows the input. But the the video falters very much. Same with the audio from the camera. I’ve tried the SDI and HDMI input from the blackmagic recorder but with the same result.Tried different frame rates etc but with nog difference.
If I put the camera feed in for example OBS I have a clean image and audio with no stuttering.
If I use instead of the camera a laptop in the recorder everything works fine.

Any ideas?