In Pokémon GO, a bonus from Adventure Week is now extended. This is confirmed by Niantic after there were issues with Adventure Sync at the event start.
What bonus is it? During Adventure Week, you can earn 50,000 Stardust and 15 Rare Candies. This was actually valid until Monday if you had walked 50 kilometers the previous week.
Now Niantic is extending this bonus for another week. So you can claim another 50,000 Stardust and 15 Rare Candies if you cover another 50 kilometers by the Monday of the week after next, which is June 17.
Adventure Week bonus extended – But why?
So Niantic explains this step: On Twitter, the developers of Pokémon GO admitted that there were issues with Adventure Sync in recent days. Therefore, Niantic is extending the bonuses for Adventure Sync for another week.
What problems were there? Some players, primarily on iOS devices, complained about incorrect measurements with Adventure Sync. They reportedly walked significantly more kilometers than indicated by Adventure Sync.
This is obviously a problem during the event, as 50 kilometers a week is already quite a lot. If you then have to walk significantly more just to reach the 50 kilometers in the game, that’s unfeasible for many trainers.

Is everything working now? With the latest update, the biggest issues have probably been fixed. However, make sure that Adventure Sync is enabled in your game, as it was turned off on many devices with the update.
How do I get the rewards? To claim your rewards, you must have walked 50 kilometers in both weeks. Then, on Monday morning at 9 AM, the rewards will be distributed. Until then, every kilometer you walk counts.