Optimization giving wrong profit

I'm getting different profit when I run an EA once on settings to the reported profit from the optimization test.
Is this a known issue in MT4? My EA doesn't use any random numbers or random functions (or anything random) and is tested on the exact same timeframe

Is this a bug or is there something I'm missing?

I'm assuming you double checked the settings used?

MT4 optimization is basically a backtest of every permutation. So if there's a difference, it's usually human error somewhere.