Hi @matt Aze - It is likely that your database underwent a planned maintenance activity or update and you used to be able to determine when an update was made but the release notes have underwent some changes: What's new in Azure SQL Database & SQL Managed Instance?
This specific issue is best handled via a Billing & Subscription Management
support request which does not require a support plan. They have the resources to investigate this exact scenario. Please see: Create a support request.