Cannot add resource to Biztalk – No .CLB data in the memory or stream

We are running a Biztalk 2016 env., and here I have experienced issues when adding a BiztalkAssembly to Biztalk using the rightclick + “Add Resource” on an Application in the Biztalk Admin Console. It gives this error:

It currently only occurs with a single DLL, containing a schema, where there are LOTS of maps that Biztalk want to remove (and redeploy afterwards) before adding this schema.

It gives exactly the same error, if I try to add the resource using BTSTASK

BTSTASK AddResource -ApplicationName:"Object.Invoice" -Type:"System.BizTalk:BizTalkAssembly" -OverWrite -Options:GacOnAdd,GacOnImport,GacOnInstall -Server:biztalkdev01\dbinst01 -Database:BizTalkMgmtDb -Source:c:\dll\BizTalk.Object.Invoice.Schemas.CDM_Invoice.dll

It also makes no difference, if I run the BTSTASK in a standard CMD or as “Administrator”

The only thing that works, is if I add the resource from another directory, than the one I added it from the previous time. In the example above, it works, if I change the source to “c:\dll2\……” (and copy the DLL there)

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