I am hoping one of you can help me out. For some reason, what I believe to be returning a date is returning the value 1.

Some more input:

- Cell E2 (which is J2.Offset(0, -5)) value is 3/31/2007 (real date, not text)

- Variable myDay, which should return a serial date, is returning the value 1 as noted in the Immediate Window.

Here is the relevant code:
Sub FillOnsiteReview()

Set rng = Range("J2:J" & [B65536].End(xlUp).Row)
    Str1 = "Due in "
    Str2 = " Days"
    
    For Each cell In rng
    
        If Not cell.Offset(0, -5) = "" Then
            
            If Not IsDate(cell) Then
                
                On Error Resume Next
                myDay = DateSerial(Year(cell.Offset(0, -5)), _
                    Month(cell.Offset(0, -5)) + 3, EndMonth(cell.Offset(0, -5), 3))
                myDay1 = Application.WorksheetFunction.WeekDay(myDay, 2)
                myMax = Application.WorksheetFunction.Max(myDay1 - 5, 0)
                On Error GoTo 0
                
                Debug.Print myDay
                
                If Date > myDay - myMax Then
                    cell = "Overdue"
                Else
                    numDays = myDay - myMax - Date
                    cell = Str1 & numDays & Str2
                End If

            End If
        
        Else
        
            cell = ""
        
        End If
        
next1:
    
    Next cell

End Sub
Here is the code for the UDF "EndMonth":
Function EndMonth(Dt As Date, Optional numMonths As Integer) As Integer
' Returns the last day of the month x number of months after specified date
' (similar to EOMONTH Excel worksheet function)
    
    If IsMissing(numMonths) Then numMonths = 0
    
    Select Case Month(DateSerial(Year(Dt), Month(Dt) + numMonths, 1))
        
        Case 1, 3, 5, 7, 8, 10, 12: numDays = 31
        Case 4, 6, 9, 11: numDays = 30
        Case Else
            If Year(DateSerial(Year(Dt), Month(Dt) + numMonths, 1)) Mod 4 = 0 Then
                numDays = 29
            Else: numDays = 28
            End If
    
    End Select
    
    EndMonth = numDays
    
End Function