cTrader is only a trading platform that let traders to invest in financial markets with many useful tools.

Market price(price feeds) come from its connected Online Brokers or Liquidity Providers.

In case different liquidity providers are connected to cTraders, it is possible that these market prices are slightly different.

It is not a time lag or system error.

Not just the price feeds, but also the “depth of market” is also different by each liquidity providers. Thus you may not see the same profit/loss results in different cTraders even if you trade exactly the same on them.