Yahoo historical prices are basically dividend record dates, not payment dates. Record dates are the dates that, if you are an owner of record, then you will receive the dividend whenever they pay it. But you aren't an owner of record unless you've bought the stock at least 3 business days earlier and allowed time for the transaction payment. It looks to me like the dates shown in Yahoo are the "3 business days earlier" dates. I checked this on another stock I own (CPO) where the company-announced payment date is Jan 25, the company-announced record date is close of business Jan 4, and Yahoo lists the dividend as Dec 30.
Also, be aware that Yahoo data is generally inaccurate for ADRs. They can't seem to handle foreign currencies, or differences between #s of common shares and ADR shares. (For instance, Yahoo lists SBS's current market cap as $31M.)
So does anyone know what is up with SBS in the last week? Just the Brazilian market correction?