Update retention.mdx (#1793)

Co-authored-by: myronkaifung <[email protected]>

Author: julianneb-mixpanel

pages/docs/reports/retention.mdx

@@ -128,7 +128,7 @@ For example, if you want to look at 30 Day LTV (Lifetime value) of e-commerce us
 
 #### 'Streak mode' 
 
-“Streak mode” is mostly meant to count unique users doing consecutive actions across time intervals. 
+“Streak mode” is mostly meant to count unique users doing consecutive actions across time intervals. If the birth event and retention event are the same, the birth event will count towards the streak.
 
 For example played a game for 5 consecutive days since sign-up, or visited the doctor for 8 consecutive months since registering for a clinic.