In January 30, 2023, I ran a backtest covering 2018-2022. Yesterday, April 30, 2023, I reran the same test with identical code but I got different results. Why might this have happened and should I be worried?

Running the same backtest twice yesterday produced the same results. The algorithm uses daily resolution.

I'm unable to attach the backtest. When I try, I get the following error: Error occurred during the process. If the problem persists, please contact support@quantconnect.com