Something must have changed then, likely with whatever parameters you’re giving to the current request. That said, we can’t help if you don’t provide the needed information; the request format doesn’t tell the full story. The exact request and server response are needed to diagnose why a particular request is being rejected.
HTTP 400 means “bad request.” So your request is likely malformed or unexpected in some way. That’s the most that can be said without server logs or the exact request to inspect.
I’d have to look at the code to be sure, but I’d guess it converts the timestamp into the browser’s timezone. You could test this by changing the timezone on your computer and seeing how Lemmy displays it.
At least that’s how I’d build it. Keeping backend times in UTC and then converting on the frontend to the user’s set timezone is generally a best practice. Using non-UTC times on servers is just asking for trouble.
Yup, it’s expired.
Private != anonymous. Saying “we don’t collect logs” really doesn’t mean all that much as there’s still many, many ways to track and uniquely identify you. That said, if you want to shield your IP from an instance using a VPN is your best bet rather than relying on someone’s pet Lemmy instance to not store logs or delete them after a period of time.