MS Word INCLUDEPICTURE + MERGEFIELD Quick Parts don't update picture

Question

I'm experiencing an issue with MS Word Quick Parts INCLUDEPICTURE and MERGEFIELD.

I have a Word document which is linked to Excel worksheet "Data" though Mail Merge. This is the structure of the Excel workbook:

[worksheet Data]

| Entry | Nation  | Nation_Img                                                | PassFail | Pass_Img                   | Fail_Img                   |
| ----- | ------  | --------------------------------------------------------- | :------: | -------------------------- | -------------------------- |
| A0001 | Italy   | =CONCAT("C:\Users\Flag\";VLOOKUP(B2;Utility!A:B;2;FALSE)) |     X    | C:\Users\PassFail\Pass.png | C:\Users\PassFail\Fail.png |
| B0001 | Italy   | =CONCAT("C:\Users\Flag\";VLOOKUP(B3;Utility!A:B;2;FALSE)) |     X    | C:\Users\PassFail\Pass.png | C:\Users\PassFail\Fail.png |
| C0001 | Finland | =CONCAT("C:\Users\Flag\";VLOOKUP(B4;Utility!A:B;2;FALSE)) |          | C:\Users\PassFail\Pass.png | C:\Users\PassFail\Fail.png |
| B0002 | Germany | =CONCAT("C:\Users\Flag\";VLOOKUP(B5;Utility!A:B;2;FALSE)) |     X    | C:\Users\PassFail\Pass.png | C:\Users\PassFail\Fail.png |
| A0002 | Italy   | =CONCAT("C:\Users\Flag\";VLOOKUP(B6;Utility!A:B;2;FALSE)) |          | C:\Users\PassFail\Pass.png | C:\Users\PassFail\Fail.png |

[worksheet Utility]

| Nation_Name | File_Name   |
| ----------  | ----------- |
| Austria     | Austria.png | 
| Finland     | Finland.png |
| Germany     | Germany.png |
| Italy       | Italy.png   | 
| Spain       | Spain.png   |

I have inserted the following quick parts in Word document in order to display the picture of the national flag depending on the name of the country:

{ INCLUDEPICTURE { MERGEFIELD Nation_Img } \d } 

Unfortunately, the picture is loaded but it is not updated along with the country for each record, unless I manually update the quick part (ctrl+A and F9) for each and every record. This leads to the creation of an incorrect Mail Merge.

Funny thing, the following combination of quick parts (used in a different part of the Word document) works flawlessly and the picture is updated automatically for each record:

{ IF { MERGEFIELD PassFail } = "X" { INCLUDEPICTURE { MERGEFIELD Pass_Img } \d } { INCLUDEPICTURE { MERGEFIELD Fail_Img } \d } } 

Could somebody please help? Thank you very much in advance!