Fox Van RC Clunck on Full Extension

G’day guys,

My friend’s bike just had a shock upgrade to Fox Van RC with Titanium Spring. Since he bought it 2nd hand, he serviced it right after.

When it came back, it clunk on full extension, even on slowest rebound. He had it serviced again and came back the same.

My friend and I have checked the bike to make sure the linkage clearance and everything, and sure the noise came from the shock itself. We even tried to fit another shock to make sure the frame’s alright.

Any ideas how to fix this?