Mesh Leaks are caused by the TAU mesher not being able to render the mesh for very small objects or small regions of intersections with high enough fidelity. To remedy, force HFSS to use the classic mesher. go to HFSS -> Mesh Operations -> Initial Mesh settings select the second tab in the window and select the radio button for Ansoft Classic Mesh. Also, in the case of ACIS errors, go to Modeler -> Validation Settings and set to Warning only. This will have HFSS classic mesher create a mesh irregardless of an ACIS error.
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