https://support.microsoft.com/en-gb/topic/kb4551220-fix-assertion-error-occurs-when-you-run-resumable-index-build-statement-in-sql-server-2856a6b1-9c41-a040-fb3d-e01c8ded6fb3
KB4551220 - FIX: Assertion error occurs when you run resumable index build statement in SQL Server...
FIX: Assertion error occurs when you run resumable index build statement in SQL Server