Symptom
The distortion lives in undifferentiated aggregate retention metrics — total signups and blended retention rate blend all acquisition sources together without revealing that recent cohort waves are retaining at systematically lower rates.
Cause
New acquisition waves from paid and promotional channels enter with lower intent than organic and referral cohorts — pulling the blended retention average down as the mix shifts toward lower-quality sources.
Impact
Retention declines over time lowering expected LTV per cohort wave — growth that appears strong at the acquisition layer is reducing lifetime value at the retention layer without triggering any dashboard alert.