During the first huge dumps on nearly all alt coins dbix just remain stable vs. BTC, it just reacts now with some slight delay - the same happend already when BTC / many alts had huger changes, DBIX also remain in the first step stable and reacts later.
I guess some people might sell their dbix to get into other coins which are down to profit when the coins get up and then they can buy back cheap dbix (so twice profit).