Question about Mandatory Overtime

So I saw a listing for a job where almost every employee review complained about constant mandatory overtime and some of these date back to before COVID. None of these reviews are for the department the listing is for, so I applied. Still, I'm worried this is a huge red flag, though I'm struggling to think of why a company would have this problem for this long that, by all means, is costing them a lot of money that could be saved by just hiring more