The spectator camera is being activated and set to 0,0,0 even when there is nothing being replayed.
This ignores the existing userHeight default in the scene.
I had to fix it via hard coding -
<a-scene avatar-recorder avatar-replayer="spectatorMode: true;loop: true;spectatorPosition 0 0 1.778">
My expectation was that even with spectatorMode active etc, if there is nothing to replay, then the default camera should be respected.