China announced plans to slap an additional 25 percent tariff on vehicles imported from the United States on Wednesday and reports have suggested American-made crossovers are being held up by customs officials in the country.

Yesterday, Reuters said Daimler confirmed authorities are inspecting crossovers made at the company’s plant in Tuscaloosa, Alabama for potential problems. Little else was known about the incident, but an unverified document suggested officials were examining the GLE and GLS for rear brakes that were “insufficient.”

Authorities are reportedly examining crossovers built between May and June. A Daimler spokesperson said they are “working with the relevant authorities to resolve the issue.”

While the situation appeared to be an isolated incident, a new report from Reuters says the American-made BMW X4 is also facing a similar issue. In that case, authorities are preventing the delivery of 400 crossovers built between April and June.

While the timing seems suspicious, it’s unlikely the trade dispute between China and the United States is causing the problem. BMW told the publication the X4s are part of a recall that impacted around 19,000 of their crossovers. The automaker said the recall was the result of a supplier that delivered rear brake calipers which could potentially be faulty.

Given the focus on rear brakes in both cases, it’s possible that Chinese authorities are examining the Mercedes crossovers to ensure they didn’t use the same rear brake calipers as the BMW X4. Regardless of the reason, the issue appears to be safety related and not politically motivated.