In my opinion this should be working:

Code:
. dis %tm monthly("201901", "YM")
      .
but it is not working, it returns a missing value.

Then this is working, while in my opinion it should not be working:

Code:
. dis %td date("201901", "YM")
01jan2019
And finally this is working as it should, and I know how to use this fact to resolve the problem above:

Code:
. dis %tm mofd(date("20190101", "YMD"))
 2019m1
My question is: Is the the behavour of -monthly- a bug that I should report to Stata Corp? Or am I doing something wrong and -monthly- can be made work if used in some more appropriate way?