Microsoft.Interop.Office.Excel assembly reference disappears

A custom code in VB .Net started from Invoke Code has issues when Microsoft.Interop.Office.Excel is referenced. Even if the reference is placed, it disappears every time the code is run once or when we try to edit the Invoke code block.

A workaround is to create a variable of type Microsoft.Office.Interop.Excel.Application in the Excel Operations scope.