Some Panasonic executives are expressing hesitation about new investments with Tesla in battery manufacturing, according to a report out Thursday in the Nikkei Asian Review.

Tesla and Panasonic were expected to set up a new factory together in China, where they would make cars and lithium ion battery cells under one roof. They have an arrangement like this in the U.S. already at the Tesla Gigafactory 1 in Sparks, Nevada.

Panasonic CEO Kazuhiro Tsuga acknowledged on an earnings call Thursday: "Tesla could in the future launch full-fledged production in China, and we could produce jointly."

However, un-named Panasonic executives painted a different picture, according to Nikkei Asian Review, telling the outlet that plans were "not solidified yet" and "nothing is set in stone." Tesla's delays in making previously expressed production targets for the Model 3 cut about 20 billion yen (about $183 million) from Panasonic's operating profit for the fiscal year ended March 31, the report says. Anonymous Panasonic execs also expressed concern to Nikkei at the way Elon Musk treated Wall Street analysts in a recent earnings call.