This was not a “flimsy” case.
"The Working Group recalls that it is inherent to the proper exercise of judicial power that it be exercised by an authority that is independent, objective and impartial in relation to the issues dealt with, as asserted by the Human Rights Committee in relation to article 9 (3) of the Covenant. In the present case, the Working Group is of the view that Judge P did not act in a manner which was independent, objective and impartial in relation to Mr. Donziger’s case. Consequently, the Working Group concludes that the imposition of pretrial detention upon Mr. Donziger was in violation of article 9 (3) of the Covenant. "
[1] https://www.ohchr.org/Documents/Issues/Detention/Opinions/Se...
But then I must admit, that I do not have a very high opinion of "arbitration courts" in general, as often they seem to have various conflicts of interests with regards to how they earn money by being paid by parties bringing the cases (i.e. deciding against the interests of a party which usually provides high-income cases, would risk the court's own financing).