Data Validation List Not Working At Startup

[Drivium]

My validation list source formula is:

=OFFSET(E$1:E$5,MATCH(C94,LEFT($B$3:$B$87,LEN(C94)),0)+2,0)

When I first start excel, the drop down does not work. If I open up data validation and just click ok (leaving formula as is) it starts working again. Could it have something to do with my workbook_open script?:

Sub workbook_open()

Dim OL As Worksheet
For Each OL In ThisWorkbook.Worksheets
With OL
.EnableOutlining = True
.Protect Password:="", Contents:=True, userinterfaceonly:=True, AllowFormattingColumns:=True, AllowFormattingRows:=True
Application.ScreenUpdating = True

End With
Next OL
End Sub

TIA

 

[Drivium]

I can upload the spreadsheet if that helps.