All of Baseball Reference's batting game logs' slash lines appear to be completely wrong

Update: BBRef is aware of the issue and making fixes. Logs that get the most page views and logs from 2000-2024 were fixed first, with the rest coming later.

Long story coming ahead, but if you use Baseball Reference at all, you should read this.

I noticed this first because last night I wanted to talk about 2011 Zack Britton's hitting where he only hit in three games and went 5-8 with a homer and a double, but noticed that his game logs page was a little funky. First of all it, gives him a slash line before he makes a plate appearance, that's bad. Second, this slash line changes after his first start, that's also bad. Third, his slash line changes again at the start of September for literally no reason, just to change back to the real number. I stared at this for about five minutes, trying to think of a reason that this could've happened, with no answers.

For some reason I then pulled up Terrance Gore's 2019 batting logs to see how it would treat a player that appeared on the basepaths but didn't bat, and it was also broken. The slash line again generates without plate appearances, then disappears somehow only to return when he makes an actual plate appearance, which then gets his slash line wrong because this is his first plate appearance and he hits a single. He should be batting 1.000/1.000/1.000 but he isn't. It then jumps around, sometimes resets itself, and just decides to give him a .500 ops for no reason. In a game where he went 0-4, his slash line jumps 100 points.

Now i'm getting weirded out, so I go to my happy place as a Brewers fan: 2018 Christian Yelich. To my not surprise at this point, it is also messed up. It claims that his slash line after his first game was .314/.389/.573 despite going 1-4 that game. At random points it dips below .500 for no reason. For May 14th, it shows his slash line for that single game. It craters at the start and of June, as well as randomly throughout the season. On the last game of the season, famous game 163, it lists his slash line as .194/.289/.250, comedically showing his actual real life final slash line directly underneath it.

So I take a step back and simplify it a little: let's look at Shohei's 2024. DH only, uncomplicated. And it's wrong, it's all wrong, the slash lines are just made up. It does it considerably less often but it will still crater out of absolutely nowhere, just to rebound shortly after. The end of season slashline doesn't match with the final game line like it should. I don't understand.

Barry Bonds' 2004 is wrong, Ted Williams' 1941 is wrong, Babe Ruth's 1923 is wrong, I think they're all wrong. An archive of Ted's 1941 from 1/31 is correct, so this was a very recent error, but I still have no clue what could've possibly broken things this bad. I don't know what can be done about this. I assume the staff there know, I only discovered this last night, but this is a big problem. Hopefully it's a silly little coding error that takes tweaking a few lines of code to fix, but hopefully batting game logs reflects the correct numbers soon.