They're conflating episodic memory retainment with consciousness. Consciousness process may result in things to store in memory, but, not being able to store those things long term doesn't necessarily mean consciousness was missing in that moment.
After a brain injury, I had my memory truncated to around 30 seconds for a short time. I would claim I was probably less conscious because the time I could perceive and predict was truncated so incredibly small that I couldn't make sense of the past or future. I could perceive the present just fine, but it relatively meaningless/without context, so couldn't be extrapolated. I think something related to that will end up being a definition of consciousness: meaningful extrapolation of past experience. Or, maybe simply, a meaningful persistent world model, with an update loop.