Our decision to list sub-collections of expansions as separate expansions proved to be quite controversial. We did a poll on Discord, and it seems that the vast majority of you would like to see this change reverted. For that reason, we decided to immediately revert this change, listing sub-collections as part of their expansion again.
We're aware that a large minority still liked this change, which is why we aren't ditching this idea entirely. We're currently looking into new ways of listing/customizing expansions, possibly integrating it with the future custom card list feature.
If you have feedback regarding these changes, please let us know. Thanks!