First go thru the TextBoxes and remove all references, Ex:='Cover Sheet'!$U$34. Leave them blank or empty.
In the code module of the Template Sheet with Text Boxes add this code.
[VBA]
Private Sub WorkSheet_Activate()
TextBox1.Text = Sheets("Cover Sheet").Range("U34").Text 'Change T-Box name and Ranges as needed
TextBox2.Text = Sheets("Cover Sheet").Range("V35").Text
End Sub[/VBA]
That code will run in its entirety every time the text box sheet is activated. You can add a line to prevent it from running all the way through if textBox1 has some value. Put it as the top line under the Sub declaration.
[VBA]If TextBox1.Text <> "" Then Exit Sub[/VBA]