Grizl cf seat post or clamp help

Bike has about 1600 miles. I've done about 80% on gravel roads but specifically 2 rides on very bumpy washboard sections. I get off the saddle as soon as safely possible but that's enough to start the process of the post dropping. I cleaned re-pasted and adjusted to specs the first time. Yesterday same thing. I overtightened the clamp but still the post kept dropping on any big bump. I don't see any cracks or anything abnormal on anything. Could the clamp just not be good? Anyone have this experience?