strange behaviour of LeftCosets

I have noticed the following, strange and bad behavior of listing elements in left cosets, which is shown in the following example:
```
gap> G:=SymmetricGroup(3);;
gap> H:=Group((1,2));;
gap> List(LeftCosets(G,H), List);
[ [ (), (1,2) ], [ (1,3), (1,2,3) ], [ (1,2,3), (1,3) ] ]
```
Using `AsSet` instead of `List` works as expected.