Userform runs Initialize sub @ beginning of textbox AfterUpdate event w/out being called

I have a textbox where I have setup some code in the AfterUpdate event that is intended to take the value entered into the box and "do stuff". I have struggled to get it to do stuff, and finally realized that one of the problems is because my me.textbox.value is always coming up empty even when there is text entered into the textbox on the form and I've pressed enter. I know very little about the step-through functions in VBA and finally figured out how to F8 my way through my textbox AfterUpdate sub. I discovered that the very first thing it does, before even making it to any of my "do stuff" code, is to run the userform initialize sub. In the initialize sub I had previously written code to explicity set the value of the textbox to "" so that it would be clear upon opening. What is tripping me up is that my textbox afterupdate sub does not call the Intialize sub anywhere in its code. Why is it making that jump?

Below is the beginning of the AfterUpdate code, which is a hot mess right now because of all the different coding things I'd tried prior to discovering the null textbox value issue.

Private Sub fPanelNumi_AfterUpdate()
 Dim testcell
 Dim i As Integer 'row position of a panel number
 Dim j As Integer 'the quantity of discrete values with a panel number string
 Dim k As Integer 'loop counter for the string values
 Dim m As Integer 'low value of a range in the panel number string
 Dim n As Integer 'high value of a range in the panel number string
 Dim forstopper As Boolean
 Dim nArray As Variant
 Dim nPanelArray As Range
 Dim RowCounter As Integer
 
 
 'fix this so that entering a part number doesn't pull in random data in instances such as when creating anew panel.
If OBtnNewPanel.Value = True Then
    Else
        OBtnLoadPanelI.Value = True Or OBtnLoadPanelN = True
End If
    
 'Make DataEntry active
 Worksheets("DataEntry").Activate

 RowCounter = WorksheetFunction.CountA(Range("D5:D200"))

Set nPanelArray = Range("D5:D200")
 
i = 1

forstopper = True
    Do While i <= RowCounter And forstopper
        
        'MsgBox InStr("106-108", "-")
        Me.fPanelNumi.Value = Me.fPanelNumi.Text
        MsgBox Me.fPanelNumi.Value
        nArray = Split(nPanelArray(i, 1).Value, ",", , vbTextCompare)
        j = WorksheetFunction.CountA(nArray)
        k = 0
        Do While k <= j - 1 And forstopper 'This searches for a number within a string of comma delineated numbers, ex 106,107,108,109
            If InStr(nArray(k), "-") = 0 Then
                If nArray(k) = fPanelNumi Then

Thanks.