After my test, this formula works well,
if you want this new measure as below:
new previous month = CALCULATE(SUM(Table1[Value]),PREVIOUSMONTH(Table1[Originated].[Date]),MONTH(Table1[Originated])=MONTH(TODAY())-1)
here is pbix, please try it.
If it is not your case, please share some data sample and expected output . You can upload it to OneDrive or Dropbox and post the link here. Do mask sensitive data before uploading.
Community Support Team _ Lin
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.