Simplify a single tree branch

I am posting here again, since the bug report is still unanswered, maybe someone has a workaround.

So I am merging 2 data streams with different path depths, like {0},{1},{2} and {0;0;0}, {0;0;1},{0;0;2}. So when I simplify all the inputs to merge, it does what is expected and bundles everything together into the {0},{1} and {2} lists.

But now the patch can also produce just single branches, so one in the format {0} and one in the format {0;0;0}. Simplify does nothing to those paths and therefore merge results in two branches.

Anyone have a workaround for simplifying single data streams (but not flattening). I know I can just check the number of branches and then switch to a different merge that flattens the inputs, but I would rather use just a single node which accomplishes this. To be honest, I dont understand why simplify ignores single branches.

Here is another example.

2 branches:

1 branch: