Off the top, Augusto Montano and Brandon Moreno, both from Mexico, were both cleared of any wrongdoing by USADA, the UFC drug testing agency, because they had previously issued a warning that Mexico was full of potential contaminations for that substance.
I think one or two Chinese fighters were cleared for the same reasons.
I hear the amounts Canelo tested positive for are quite low as well, so fingers crossed the agency in charge clears him too.
RE: Boxing SUPER FIGHT to be canceled?