NVDA, for just one example, often shows in your quotes & portfolios with a number way off from real number - which you can check anywhere else (NASDAQ, Brokerages, your own Historical values chart!)
this leads to wild inaccuracies in portfolio values, daily values, etc. as your program does not compensate for this.. next day it either uses its incorrect value, or - more often - replaces the wrong value with current day correct one, and leaves previous day misinformation intact.

this is obviously bad, as day-to-day portfolio values can be quite off, and they remain so due to the random behavior going foward.

please look at NVDA to start - just in Jan 2026 for example - and you can see how inaccurate end of day /final quotes are in your program & portfolios vs. what they should be.
the historical data itself in your program is good - but that does not influence the mistakes calculated elsewhere - sadly!