"In response to these complaints, the FCC issued a formal citation to warn the company that it must comply with these requirements. Following further complaints, the Commission ordered the company to provide information on its marketing of AV transmitters, yet HobbyKing provided no further response, as required by law. The Commission thus proposed this fine in 2018 and adopted it today."
Source: From a statement by the FCC, explaining a massive $2,861,128 fine demanded of HobbyKing over issues with their drone products.