Omaha, we have a problem. BYD, the China-based vehicle maker that's about 10 percent owned by Warren Buffett ("The Oracle of Omaha") is facing questions about the reliability of electric buses that are targeted for use by the city of Long Beach, CA, after cracks were found in some of the buses' frames during their testing period, according to the Long Beach Business Journal. The culprit may be substandard welding on the so-called "engineering" buses specifically being used for strength testing before being put into use. BYD says the bus cracks are "common" during that particular stage of strength testing.

Additionally, BYD was fined $100,000 by the state of California for alleged violations of minimum wage laws, according to The New York Times. BYD, which has also sold buses to the city of Los Angeles and has taken over a bus-assembly factory in nearby Lancaster, CA, had brought in about a half-dozen employees from China to train factory workers. The company said the workers that spurred the California wage fine aren't subject to state laws because they're working in the state on temporary work visas. BYD's North American headquarters are in Los Angeles.

This summer, Los Angeles reached an agreement buy 25 new buses from BYD, the city's first that are all-electric, as part of a $30 million clean-air project, and said another 20 buses may be acquired. BYD says the buses, which use BYD-made iron phosphate rechargeable batteries, have a single-charge range of about 155 miles. That Los Angeles announcement followed up an agreement from Long Beach to buy 10 buses, a decision that South Carolina-based Proterra blasted because of what it said were questions about the vehicles' reliability and the fact that the buses are made overseas.