This may be a market/exchange fragmentation issue, but I was not looking at Havelock.  It appears that they are issuing shares of a proprietary fund that is made up of shares of SD, but they are not a place trading in actual shares on a 1-1 basis, so the prices they reflect are for shares of their SD-based fund (presumably with a premium on top).

I was using https://bitfunder.com/asset/G.SDICE for my data, which has fairly different values (looking at the 3- and 6-month charts)