IF statement for date range

Hi there, 

Trying to post a list of gifts and have a dynamic card drawing from dates added. The goal is to list a range of dates added if there are more than one distinct value for date added. To do this I am using the First and Last Date functions to create that range and if the distinctcount < 1, return the value in the list. However, I am encountering an error in the if false statement where it is saying that 'date added' column is not found but it is found in the if true statement. I can build a function for listing the range separately but when creating this IF statement, I have not been able to crack the code. Any help would be greatly appreciated. Thanks!

IF(
    DISTINCTCOUNT(PA_DGR_Liam[date_added]) > 1,
    FIRSTDATE(PA_DGR_Liam[date_added]) &" - "& LASTDATE(PA_DGR_Liam[date_added]),
    FORMAT(PA_DGR_Liam[date_added], "MM yyyy")
)