Your account is configured to only count purchases that happen within 24 hours of a click. That's reasonable for impulse buys. But Lulu sells by the case and via subscription — people discover a flavor, read a few reviews, and often order 2–4 days later. A 1-day window hides most of those conversions.
Meta still sees the purchases happening — but your dashboard doesn't. Switching to 7-day click is one settings change, and reported ROAS typically jumps 8–15% with no other action.