You can try this then. (not certain it will work)
Step 1.
Insert a command button from the developer toolbox on slide 1. (Show the developer tab in File>Options >Customize ribbon if not already done)
In Home > Select > Selection pane set the button to NOT visible. This is needed to make the code run reliably,
Step 2
Alt f11 to open the Code editor and INSERT > Module
Paste in this code
Code:
Sub OnSlideshowPagechange(SW As SlideShowWindow)
Dim osld As Slide
Dim oshp As Shape
Set osld = SW.View.Slide
On Error Resume Next
For Each oshp In osld.Shapes
oshp.LinkFormat.Update
Next oshp
End Sub
Run the show and update the excel file see if it works - should update the nest time the page shows