KLA Corporation (KLAC), a maker of process control and yield management solutions for the semiconductor industry, inserted new language in its latest quarterly filing indicating it may have to refund certain Chinese customers no longer allowed to receive the company’s products.

Though the company says it obtained “some” export licenses that allow it to continue selling to Chinese customers on the U.S. Entity List, KLA inserted new language that suggests it may not have received all of the licenses for which it has applied. Specifically, KLA added the following list when when warning it generates most of its sales outside the U.S.:

“Required refunds for customer prepayments resulting from our inability to ship to certain jurisdictions, especially for customers in China as described in more detail below. If we are required to make such refunds, our cash flows could be negatively affected.”

KLA’s dependence on China has grown recently. Last year China accounted for 29% of revenue, up from 26% the previous two years. Later in the filing, KLA appears to confirm it has not yet received permission to continue selling to Chinese customers that have prepaid:

“If pending and future license applications are not granted, the potential impact could be material and could harm our RPO or require us to return substantial deposits received from customers in China for existing purchase orders.”

The disclosure came after the market closed on a Friday.