Updated 2 test cases to outline two major issues with the new hydration (at least i think that it has to do with the problems):
1) When the result set is in a custom order, components may be doubled (this already occured half a year ago though the symptoms were different (items were assigned to the wrong collection).
2) Accessing related components that are already loaded (but empty) results in lots of extra queries. The only way to get around that is do wrap an isset() check around nearly all places before accessing a relation. This was not the case in earlier revisions though at that time an isset() was sometimes needed, too to prevent extra queries. But now it seems to be necessary everywhere.