Quote Originally Posted by Shookbeast View Post
(“Current day” is tricky because apparently time has a loose relationship between each reflection. One planet may have existed for 1000 years post-sundering, while on another it’s only been a few minutes since the sundering.)
There's still a definite shared "current day" from shard to shard even if the lengths of time since the Sundering differ.

As far as we've been made aware, at least, time is still moving forward on each shard and if you, say, travel from Source to First and back again you are always only in one place across all the shards at any given time, and you'll return to the Source later than you left it.