Backtest-results-worse-on-first-execution

For at least a couple months now, I've noticed this weird behavior with my strategies, where if I run a backtest immediately after opening them, the overall profit percentage is a bit lower than expected. However, if I make some sort of meaningless change, like disabling and then re-enabling a condition block, save and run the backtest again, I get a higher profit percentage result from that point onwards.

Any idea what might explain something like this? Kind of feels like a small rounding precision discrepancy which is somehow rectified by re-saving the strategy.