Not only is it okay for characters to be out of sync, it's also widely used in nearly any major fiction work that uses multiple POV's.
As The Doctor said:
"People assume that time is a strict progression of cause to effect, but actually, from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly... timey-wimey... stuff."
The same applies with writing.
What it means is that the more Points of view you have, and the greater area they cover, the more you can advance and regress within the setting timeline to make your story work. And it is a popular and successful took used by some highly successful authors, and it allows you to explore, in depth, events and situations behind your major plot points:
Robert Jordan did it in his Wheel of Time series - multiple main characters that ended up all over the place. Events occurring because of one character impact events occurring around another character, or you get to see the same event from a different angle. When it's done well, you get a much more immersive setting.
George R R Martin with Game of Thrones - again has multiple characters and events that occur generally in a linear fashion but has the flexibility to really develop the story and setting.
Steven Errikson and his Malazan Book of the Fallen series - similar to the two mentioned above - but goes one step further in that the books themselves aren't chronologically ordered. The published order and chronological order of events varies a great deal - but it works and flows because you are getting so much more information and a greater understanding of the setting.
There are too many other authors to mention that do this, but the one thing that it needs, and you need to keep in mind when writing, is that you must have a point of reference or fixed point in time for your readers to fully understand when, how and why some events are occurring and show the progression of each characters story.
And that's another thing - all those authors aren't just telling one story, they are telling each characters story within the greater story and that is part of why it works so well.