The Bill Gates-Warren Buffett relationship is fraying.

The Oracle of Omaha has reportedly paused his annual gift to the Gates Foundation due to the Microsoft cofounder’s ties to the late sex offender Jeffrey Epstein, according to The Wall Street Journal.

People familiar with Buffett’s plans told WSJ Buffett is delaying his decision until later this year, possibly when he releases his annual Thanksgiving letter. This is a major change, considering Buffett, 95, made a “lifetime” pledge to the Gates Foundation and has historically donated billions in Berkshire shares each summer.

Representatives for Buffett and the Gates Foundation didn’t immediately respond to Fortune’s request for comment.

Buffett wants to wait for the findings of a review the Gates Foundation has commissioned into its own ties to Epstein, per WSJ. The foundation has retained law firm WilmerHale to conduct it, with findings expected this summer. Buffett has given more than $47 billion to the foundation between 2006 and 2025, according to Reuters.