leaking "each" variable with nested childen/model binding

see the attached example, it shows the problem with 2 workarounds.

the outer "each" variable replaces the "null" value in the combobox' first item.
Resulting in the first label rendering incorrectly.
Still the combobox selection correctly contains [null] just the label does not receive the "null" value, but a Reference from the outer div/s children binding.