I would agree with the way that you described the meta-set.
When you say:

Not a (meta) batch of data-sets

Do you mean, the batch is not sampled from multiple data-sets? I think my answer and his are about the same. He suggests that an episode is sampled from one data-set, and I would agree with this. I just don’t know if this is a strict requirement of an episode. What’s the main contradictory thought that you’re noticing?