I'm encountering a problem in Amplitude where anonymous user data isn't being automatically merged with their userId upon login. My application consists of two independently functioning parts that share the same domain.

Here's the user flow and what's happening:

1. Initial Visit (/home): The user lands on the main page, navigates, and adds items to their cart. At this point, the userId is not yet assigned, but a deviceId exists.

2. Login/User ID Assignment (/checkout): The user proceeds to the cart, which is part of a second application on the same domain. Here, the user receives a userId, and the deviceId remains the same.

3. Amplitude Discrepancy: When I check Amplitude's user proifiles tab, the anonymous user profile and the identified user profile are not being merged

This results in fragmented user journeys, making it difficult to analyze the full user experience from initial anonymous interaction to authenticated activity.