Yes, custom policies in Azure AD B2C (adb2c) can internally use and consume Graph API limits, depending on the operations performed within the policies. In your case, where custom policies are utilized to update user information during the login flow and create users during the sign-up process, it's likely that Graph API calls are being made.
Azure AD B2C relies on Microsoft Graph API for various identity operations. Any custom policies that involve user updates or creations typically translate to corresponding Graph API calls. Therefore, it's important to be aware of and manage the Graph API rate limits to avoid potential issues related to throttling.
To ensure the efficient use of Graph API and prevent exceeding limits, consider optimizing the custom policies by minimizing unnecessary calls, batching operations where possible, and caching data when appropriate. Regular monitoring and understanding the specific Graph API operations performed within the custom policies will help manage and stay within the allowed limits.
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