具有相同参数的相同函数如何在excel vba中产生不同的答案？

Question

以下代码：

Sub testingstuff()
    Dim x, y As Long       
     x = Find_lastest_day_events("flurry_an_output.csv", "User_Session", 4)
     y = Find_lastest_day_events("flurry_an_output.csv", "User_Session", 4)
    Debug.Print "x is " & x
    Debug.Print "y is " & y
End Sub

在立即窗口中产生以下输出：

x is 121
y is 0

究竟怎么可能？

这是功能：

Function Find_lastest_day_events(sheet_name As String, event_name As String, event_col As Integer)

    '   find the range of the last full day in a column and count the number of events for the last day
    '   use '*' in event name to just count events in range
    Dim rows1 As Long
    rows1 = Get_Rows_Generic(sheet_name, 1) ' total rows in sheet
    Dim col1 As Integer
    col1 = Range(find_last_column(sheet_name)).column ' last column number [uses address first]

    Dim last_cell As Range
    Dim full_range As Range
    With Worksheets(sheet_name)
        Set last_cell = .Range(.Cells(rows1, col1), .Cells(rows1, col1)) ' sets last_cell to the last cell in the sheet
        Set full_range = .Range(.Cells(1, col1), .Cells(rows1, col1)) ' whole last column as range
    End With

    Dim todays_date As Long
    todays_date = Date

    Dim search_date As Long
    search_date = todays_date - 1 

    Dim first_position As Long
    first_position = WorksheetFunction.Match(search_date, full_range, 0) 

    Dim last_position As Long
    last_position = WorksheetFunction.Match(search_date, full_range, 1) 

    Dim event_range As Range
    With Worksheets(sheet_name)
        Set event_range = .Range(.Cells(first_position, event_col), .Cells(last_position, event_col)) ' set the range to be searched
    End With

    Dim event_count As Integer
    event_count = WorksheetFunction.CountIf(event_range, event_name) '  count the numbe rof events

    Find_lastest_day_events = event_count
End Function

**根据评论添加**

Function Get_Rows_Generic(work_sheet_get As String, column_num As Integer)
    Dim ws As Worksheet:             Set ws = Worksheets(work_sheet_get)
    Dim rows_count As Long:                 rows_count = ws.Cells(rows.Count, column_num).End(xlUp).Row
    Get_Rows_Generic = rows_count
End Function


Function find_last_column(ws_name As String)
    Dim ws As Worksheet
    Dim rng1 As Range
    Set ws = Worksheets(ws_name)
    Set rng1 = ws.rows(1).Find("*", ws.[a1], xlFormulas, , xlByColumns, xlPrevious)
    find_last_column = rng1.Address  ' returns the address of the first cell in the last column used as a string
End Function