Invalid access to memory location when deploying Azure web app

I have an Azure web app that I'm deploying from VSTS. This was working fine previously but is now returning with the following:

2018-08-07T14:24:57.1655319Z Info: Adding directory (dsadminportal-dev\wwwroot\assets\css\plugins\datapicker).

2018-08-07T14:24:58.2654020Z ##[error]Failed to deploy web package to App Service.

2018-08-07T14:24:58.2665943Z ##[error] Error: (8/7/2018 2:24:57 PM) An error occurred when the request was processed on the remote computer.

Error: An error was encountered when processing operation 'Create Directory' on 'D:\home\site\wwwroot\wwwroot\assets\css\plugins\datapicker'. Error: The error code was 0x800703E6. Error: Invalid access to memory location.

at Microsoft.Web.Deployment.NativeMethods.RaiseIOExceptionFromErrorCode(Win32ErrorCode errorCode, String maybeFullPath) at Microsoft.Web.Deployment.FileSystemInfoEx.set_Attributes(FileAttributes value) at Microsoft.Web.Deployment.DirPathProviderBase.Add(DeploymentObject source, Boolean whatIf) Error count: 1.

This is to a slot. I deleted the slot and recreated it and it deployed fine first time but subsequent deploys fail with the above error.

Any ideas what this means?

Thanks

I found that as a workaround, publishing through the option "Run from ZIP" through the manual publishing dialog was working. But that option i think is not yet available from a VSTS task.

Solution: I finally found out, that the workaround was actually causing the issue! After deploying through ZIP, the function app setting WEBSITE_RUN_FROM_PACKAGE (formerly called WEBSITE_RUN_FROM_ZIP) was created. This was actually breaking deployment through web deploy! Deleting the setting was fixing the issue.

see: https://azureappservices.blogspot.com/2018/08/409-conflict-could-not-write-to-local.html