I made a simple scene with an animated camera then exported it with the USD ROP.

I use this command with hcmd.exe to render out 48 frames.
husk -f 1 -n 48 --renderer Redshift "C:\rs_test.usd"

It only renders one frame and then stops. Any ideas?

So I was flattening out the stage when I was exporting via USD ROP, that was the culprit.