The Turboform namespace was part of internal CRM Form rendering logic, and Microsoft has never officially supported it's use in Custom scripts. It may have worked in older versions, but it's not guaranteed to exist or behave the same way in newer versions of Dynamics 365 CRM especially in Online and Unified Interface.
I am migrating my On prem code into SAP cloud where I am facing this issue of turboform which was supported before but not by Microsoft Dynamics CRM latest versions. Any solutions for this ?