Without diving into detail that I'm not qualified to provide, trades reported on a Form T ("T trades" are something of a quirk of the OTC markets where the market makers are not required to report trades in real time if it would potentially be disruptive to the market. There is little oversight of T trades and related reporting, from what I understand, and it has been speculated that T trades could be used to manipulate markets through hiding trades from real time data and only reporting them after the fact. There are legitimate purposes too though.

Someone here can give a more technical answer, no doubt.