Is this an FX issue or a mathematical miscalculation?
Bit difficult to see in your screenshot. At history you can see the price and FX at the moment of purchase. Compare it to FX now.
Your return can be a negative value even though the sell price is higher than your avg price when the instrument currency (USD) has depreciated in regard to your account currency (GBP) for the period of owning the shares.
@George @David. My buy price was 90.05 and the current price is 95.05. That is a +6% return and yet I am down a whopping 2% total! This can’t be due to FX rate because I bought it as 1.25GBP to USD and today it is 1.26 GBP USD.