Today, I noticed that the “Missing:” option in expression column is not working as expected. Neither of the options seems to have an effect on the column values.
Thanks for clarifying. When we developed this option we were considering the use case of two columns where one of them had a missing value.
We have modified how it works so you should get a value for expressions with only one number column. Please download the latest beta and let us know if this is working for you.