At a farcical weigh-in on Monday, Solis came in 1.4 kilos overweight and only managed to get it down to 1.1 kilos overweight an hour later before refusing any further attempts inside the permitted two-hour window.
"I won't reduce my weight any more. I cannot make it because it is too cold in Japan," Solis was quoted as saying. "I ran for an hour but it didn't help. I cannot sweat any more if I move around for another hour."
Nonetheless, the overweight Solis won the scheduled main event against Daiki, one of three Kameda brothers to currently hold a world boxing title.
Though judge Robert Hoyle had Kameda winning by 115-113, both Joe Garcia and Valerie Dorsett scored it 116-112 for Solis.
"It makes me happy to win but unfortunately I could not unify the title," Solis told reporters through an interpreter. "I feel responsible for my failure to make the weight."
The nature of the title situation after a champion fails to make weight meant that Solis was stripped of his WBA version of the title for not making weight, with Kameda still able to unify it with his own IBF belt had he won.
Kameda’s narrow defeat means the WBA version is now officially vacant, but Daiki remains IBF champion because he was not defeated by a boxer who came in as a super-flyweight.
His brother Tomoki came through on the undercard, however, with a unanimous decision over Immanuel Naidjala to retain the WBO bantamweight crown.
In his first defence since beating Paulus Ambunda of Namibia in August, Tomoki outscored another Namibian on all three cards by 117-111, 118-110 and 119-109.
“I feel happy to have won the fight. I was quite confident this time but I could not fight in my style of boxing,” said Kameda, whose unblemished record stretched to 29 wins, 18 by knockout. “I want to fight better next time.”
Also on the Osaka card, Katsunari Takayama of Japan also scored a unanimous decision to retain the IBF minimumweight title against Virgilio Silvano of the Philippines.