Video sources freeze when more than one is active

[Keyboard_Failure]

Every time I load OBS, only one of my two video inputs is live. When I switch scenes or attempt to activate the other camera, one or both of the video inputs freezes and I cannot get it back by unplugging/replugging the HDMI capture card.

I've already tried uninstalling and reinstalling OBS, checking that my hdmi capture cards are both on separate USB Hubs, as well as lowering resolution etc. My scenes used to work with different cameras at similar resolutions, but I had the USB adapter for my Kinect die, thus the new second hdmi capture, and my CPU is no where near topped out.
Log can be found here:

https://obsproject.com/logs/HAIVDv6Dl5yctaN9

I'd probably just ignore the part about the Missing LUTs. those are only gone because of the uninstall/reinstall, and the problem existed before this.

 

[Keyboard_Failure]

So I've been able to rule out USB bus throughput hitting a limit. Iv'e checked with the USB Hub viewer that the cameras are not on the same hub, and both cameras work fine in individual applications. as a work around, I have one camera open in windows camera app, and using a window capture in OBS. It's not ideal, as this is probably more CPU, and another app to open to get ready for my stream, but it gets the job done.