Stange error on content building

When i build for android 9 time out of ten I get the error The process cannot access the file ‘C:\Users\andy\Source\Repos\NewEngine\NewEngine\NewEngine.Core\Content\obj\Android\net8.0-android\NewEngine.mgcontent’ according to online googling its an issue with the .net 9 version but in my test project I am using release build with .net 8 build fine for desktopGL any help appreciated