It’s fair to say the Ai Pin launch didn’t go the way Humane planned. This week, the well-funded startup is dealing with another on a long list of mounting issue. The company Wednesday issued an email requesting customers discontinue use of its egg-shaped charging case.

The warning was issued “out of an abundance of caution,” according to Humane. The company says it launched an investigation following a “single complaint” of a charging issue from a customer. Ultimately Humane determined the supplied batteries to be potential fire hazard.

“Our investigation determined that the battery supplier was no longer meeting our quality standards and that there is a potential that certain battery cells supplied by this vendor may pose a fire safety risk,” Humane wrote in an email viewed by TechCrunch. “As a result, we immediately disqualified this battery vendor while we work to identify a new vendor to avoid such issues and maintain our high quality standards.”

We reached out to company for more detail and asked whether Humane has any intention to issue a full recall or refund. Currently, the company is offering consolation in the form of two free months of its $24 subscription service.

Humane is far from the first consumer electronics company to ship products with potentially hazardous batteries. The timing of the news is less than ideal, however, as its founders have reportedly been shopping the company around to potential buyers a mere months after launching its first product.

According to the note, the Charge Case is the only Humane product affected by this news. Neither its Battery Boost or Charging Pad have been singled out by the company.