To get a quick feel, I found that DocuSign's main numbers (see above) are eerily similar to that of Box in fiscal year 2017 (both ending on 1/31) - whether it's revenue, growth, gross margin, S&M expenses or even operating cash flow. Knowing that DocuSign and Box share the same board member, Rory O'Driscoll of Scale Venture Partners, since 2010, it's hard not to make any connections here.
Above anything, raising money through ICO instead of via VCs really put a question mark, IMHO, on the founders' ability to convince, which to me is the key quality of a good founder.
While I do not have any insider information, it seems to me that the company treated manufacturer just like that, a manufacturer. Usually if a company chooses an EMS partner properly and has honest and frank collaboration, this kind of surprise won't happen, let alone switching manufacturers.