Hi – I’ve also noticed this recently (on FTSE, DAX and HS), the demo prices are different to Live and I emailed IG about the issue together with screenshots. This has the effect of making any backtesting or demo testing less reliable which of course means the usefulness of PRT software is called into question. The reply I got was frankly ridiculous and pretty much the same as Despair received. That is, they are aware that demo and live prices will be different but that they have no plans to correct this as they do not see it as a “bug”, it’s just part of normal day to day operation. Insane.
So, yes treat the prices with caution but unfortunately we have no choice but to live with it as it will not get fixed.