Hi Richard,
This seems to be a problem with Yahoo not having updated pricing available. For example, go look here:
https://finance.yahoo.com/quote/NESN.VXand you can see the last price they show is for Apr 5. When you retrieve with Fund Manager it is getting the April 5 price, thus it is reporting a price was updated, but it was for that older date. You can verify this looking at the price retrieve log (Help / Logs / Price Retrieve...).
You might want to change to use the Swiss Quote server for these securities. If you remove the .VX from your symbol, and change the investment to use Swiss Quote you can get the quotes from there. If you need help changing the quote server, see the
retrieving prices tutorial.