Recently i made a run and it showed 50 ms. But i could only get 500 or 050, i chossed 500, but what we do in this case?

I do not completely understand your question. I know that when you are doing IL's the game only shows two decimal places however this site forces us to use three. That is not a timing bug though. What you are supposed to do is add a extra 0 at the end. So for instance if you got a 1.50 second run for instance you add a extra 0 at the end at submit it as 1.500. I apologize if this does not answer your question through as again I do not quite understand it.

Yep as Zehher said.

Let's say you got a 23.05. That's 23s 050ms. If you got a 23.50, that's 23s 500ms.

Not a bug, just that the in-game sonic timers don't show 3 decimal places. It only shows up to cs (centiseconds).

Locking this as I feel it is resolved. Feel free to poke me on Discord (Von Ryder#8348) or through the Speedrun site messages if you need any more clarification.