[German]Microsoft has released the Windows 10 Insider Preview Build 19042.487 (20H2) as Update KB4571744 for Windows Insider on August 26, 2020 on the Beta Channel. The announcement was made in the Windows Blog, where you can read the list of fixes and known issues. Note: The update is also available for Insiders in release preview channel für users with Windows 10 2004 and changes the build to 19041.487.
the KB4571744 update for Win10 v2004 & v20H2 includes the defrag/optimization bugfix as mentioned by MS in their blog:
"We fixed an issue that causes the Optimize Drives dialog to incorrectly report that previously optimized drives need to be optimized again."
note – the updated DLL files for the ms defrag fix are defragproxy.dll, defragres.dll & defragsvc.dll – all 3 of them with ver. 10.0.19041.487