The National Highway Traffic Safety Administration (NHTSA) is currently investigating (pdf) two separate non-crash-related seat belt failures that occurred in newer Tesla Model X vehicles (via NBC News).

NHTSA’s Office of Defects Investigation (ODI) notes two complaints from Model X owners saying their front safety belts failed to stay connected to the seat belt anchor pretensioner. Both owners reported that the separation occurred while driving their 2022 and 2023 model-year Model X SUVs. The investigators write that “both vehicles were delivered to the owners with insufficiently connected anchor linkages.”

NHTSA first opened the investigation on March 24th and says up to 50,000 or so Model X vehicles could be affected by the issue. In both cases, the agency says “connection failure” occurred in the area where the anchor meets the pretensioner, as they “were not properly connected during assembly” and were only stuck together by friction fit. Separation occurred when “the force exerted on the linkage overcame the resistance of the friction fit while the vehicles were in motion.”

Tesla had to issue a different seat belt recall last year to fix an issue that affected over 24,000 Model 3 vehicles. Those occurred due to unrelated service center visits where techs did not reassemble the rear seat anchor correctly.