Ask HN: Can a company clawback vested stock options?

I voluntarily left a well-known tech company after the 1 year stock option vesting cliff. When notifying the company that I wanted to exercise my options (within the 90 day window) they informed me that they were exercising their right to claw back and repurchase those options.

I'm curious if this has happened to others in the tech industry. What recourse do employees have in a situation like this? What should one look out for to avoid this in the future?