Think it was a combo of folks taking profit along with a note that had already been converted but hadn't yet been sold into the float...also there was a lot of shady action on the L2 that helped drive it down...I know many argue about the reality of shorting on the OTC however Interactive Brokers had many shares available to short with...when I say shady I mean stacking the ask to ridiculous levels along with an algorithm designed to constantly paint the bid with small amounts each time the ask was smacked
That's what i observed personally
For the record it's been trading a lot cleaner since then
IMO, INTV made money by diluting their note-based Viva shares as per their 10-Q, there were many profit-takers too, and all these started panic sellings.