VTSSX Dividends - what just happened?

So I logged into Fidelity to review my accounts, and noticed that the markets were shot today (12/30/2024). However, I also noticed that VTTSX, the Vanguard 2060 Target Date Fund, had paid a dividend. Can someone explain to me how a dividend for a target date fund like VTTSX is supposed to work? I have a brokerage that is just VOO, and I have the dividends for such set to automatically reinvest. However, I do not see how I can configure my 401(k) (which is just VTTSX) to do the same, and I notice that my Roth IRA did not receive a dividend notice even though it is entirely VTTSX. Any tips helps, thanks in advance.