“Also, I wanted to mention that we have a site-- http://answers.microsoft.com that you can use in the future to report issues like this.”
“Hi Vijay--this is Andrew Stegmaier from the Excel engineering team.
Thanks for pointing out this issue. I was able to see the same thing in Excel 2013 and 2016, but it appears to work fine in Excel 2010. We take feedback like this seriously when we prioritize our engineering investments for future versions.
In the meantime, I wanted to suggest a workaround if you're blocked by this--if you first point your named range at some _other_ range in the workbook that's not a table column (e.g. =A1), then you should be able to set the input cell property of your dropdown control to this named range. Then, after the property is set, you can re-direct the range back to the table column, and everything will work fine.”