Multi-cam AR session. Problems with vsync

Hello!

So I am using multiple camera feeds for a multi-perspective AR. The "main" camera is on a Vive Pro with the Zed Mini camera. I'm using SteamVR and Zed plugins for rendering-tracking.

The other two inputs are webcams (iphones using IVCam) rendered using WebCamTexture. The iphones are connected through USB, so no wifi issue can be possible. Both cameras work at 60 fps.

I have selected "don't sync" in the quality settings. However, when the two webcams are activated, I see in the profiler that most of the frame duration is spent on vsync (slowing down to 30 fps, while it could be more than 100 without vsync). The issue happens both in editor and in build. I guess Unity automatically tries to sync all the video inputs together.

Any further information/detail/solution about that?

Thanks!