Dark Souls 3: Untended Grave lore discussion

After defeating Oceiros, you can get through the illusionary wall and enter the Untended Grave: it looks like the starting area + Firelink Shrine, but it has certain differences, as well as being shrouded in heavy darkness.

It appears to be in the past, but you don't enter it through any magical sequence, but rather you can just walk into it, which confuses me greatly.

It also has a room which isn't present in the "present" Firelink Shrine.

Is there any other example of time and space not working normally within Dark Souls which doesn't include some magical transportation sequence? (In DS1 DLC you get magically transported in time - here you just walk into a place which you can also see in the assumed present.