Angle between shell normal and solid normal must be greater than 45 degrees

I get this warning message any time I'm working with weldments larger than 2 parts: "the angle between the normal to the shell and the normal to the solid face at a shell-solid link must be greater than 45 degrees.  The link(s) will be ignored".  Can anyone tell me what Simulate is doing?  The diagnostic tool highlights elements around these connections but as far as I can tell connectivity is maintained.