Soft-launch: 6% click-rate. Full-launch: 0.5% click-rate. What gives?

I sent out the MR4S launch email today. ~6,000 recipients.

Soft-launched to 80 people, got a 6% click-rate.

Full-launch to the remaining 6,000, got a 0.5% click-rate.

Both open-rates at ~13%.

What gives? Why would this happen?

Emails were sent within 30 mins of each other.

Just curious if anyone has good insights here.