Hello there,
Consider this very simple scenario,
User Installs the app → Anonymous ID is generated by RevenueCat (this ID is searchable in the RevenueCat’s Dashboard) → User perform a sign in and newAppUserID is provided by us. Now, the newly provided app ID is an alias and the anonymous ID is the Original App User ID. Everything is good!
Now →
User reinstalls the app, a new Anonymous ID is generated by RevenueCat (this ID is also searchable in the RevenueCat’s Dashboard), User perform a log in → RevenueCat detects that one of the customer already has this alias (Our own App User ID) and merges.
Now what about the customer that was created during the re-install of the app?