I do!
While the story itself is told mostly chronologically, there is the odd scene here and there where I explore bits and pieces of the past.
But for my shorts however, those are a free-for-all when it comes to time and place. I have several in mind that would go back in various timespans. Some only a few months (my upcoming anniversary special is set 6 months prior to the events of chapter 1 for example), but I do have some that would take place yers before the start of the story.
I don't plan on doing making shorts that take in place in the future though. At least, not until the main story is finished. I don't want to spoil anything and feel like the shorts should build on already established information, provide a new insight moving forward.