children does not check whether returned nodes are nodes

[adamjanicki2]

The children function needs to use the isNode function from the context to check whether nodes are actually nodes

[LeaVerou]

I believe it doesn't do that only when following getChildProperties() (or what replaces it) as a perf optimization, the assumption being that then it's on the author to supply correct information.
That said, it should check that they are truthy.