How does WebXR handle AFrame camera pose and tick events?

[riebling]

Apologies that this is a question and not a proper Issue, but seeking help from those with more expertise:

We've got an AFrame scene (http://xr.andrew.cmu.edu/arena-xr) that publishes camera pose (location and rotation) by reading these values from the main camera scene element on every 'tick'. It's pretty cool because multiple users can see each other move about in the scene in real time on a variety of devices that support WebVR/AFrame/THREE.js.

It seems that when viewing this scene in WebXR Viewer on iOS, that information is never available or updated. Might that be because not all of AFrame is running, that tick events (especially for the main camera) are not being fired?

I've been digging through code but felt emboldened to try asking 'real people' for help - thanks!