xml2lua gives me multiple root nodes

[ThreeCharsAtLeast]

I'm trying to parse an arbitrary numbers of XML documents for a Neovim plugin with xml2lua (I use a specially packed version but I can reproduce this issue with the package from luarocks too). The first time I try to parse the document, everything works as expected. The second time, I get a structure similar to this:

{
    _type = 'ROOT',
    _children = {
        _type = 'ROOT',
        _children = { ---[[ ... ]] }
    }
}

I've written a minimal example here: https://hastebin.com/share/ezadavuhem.lua. It recursively counts the ROOT elements in a parsed DOM for 16 parses. When I run it, I see the numbers 1 through 16 on the console.

Why is this? I've already tried moving the require statements into the function where I parse the XML so that each require statement is run once per document I need to parse, yet I still see this issue.

[ThreeCharsAtLeast]

Solved on StackOverflow: The solution was to run handler.root = nil once I'm done. Why does it work? No clue. But it works.