I would say it is more common than it should be and I definitely experienced it multiple times in my career. A few tips:
- ask lots of questions and listen carefully - you'll figure out quickly who knows what's going on and will be the ones you can rely on, as well as the other ones
- take the initiative to meet with your management peers in the departments you need support from; ask questions, listen, and especially find out what you can do for them
- don't be afraid to ask questions of your manager; if they are any good, they will know that is a sign of competence, not weakness
- try not to make any major decisions (organizational in particular) for 90 days if that's possible
- take lots of notes on what you observe and review all of them periodically - you'll see trends as well as things that appeared one way at the beginning but are really another way once you have more data
Good luck!