Some New Zealand ancient DNA experts have concerns about the analysis:

“So, the data that the whole argument is based upon is DNA from one sample that was produced without using standard ancient DNA protocols and analysed without using standard ancient DNA authentication methods. The data presented, to an ancient DNA researcher, ring alarm bells and appear very much like damaged and/or contaminated DNA."

https://www.sciencemediacentre.co.nz/2018/04/13/when-did-swe...