This imputation issue has been the thorn in my side for the past two weeks while trying to run a regression model. I followed everyone's advice but now the imputation macro is changing up the output. Some times I will have "right_fieldname" in my regression configuration before I run my workflow, and then after I run the workflow those right fields disappear and my regression is left with only 2 fields in the configuration selected. So then I'll select the original field names that no longer have right before them, and the regression gives me an error that fieldname is missing values (which was the whole reason I used the imputation macro). I'll delete that macro and insert imputation_v2---create record error. Delete that one, put back the original one, same error. Install from comments above, and the output issues. *sigh*.
Counting down the days until there is a new alteryx update released... until then, adding isnull in my SQL.