Many Pokémon GO players were surprised by the current weekly reward. For many trainers, the Adventure Sync counted more than 10 kilometers of distance.
This is how it actually works: The Adventure Sync of Pokémon GO counts the kilometers walked by the player throughout the week. Every Monday, there is a reward based on how much one has walked. Rewards are given for 5, 25, and 50 kilometers.
This problem exists now: However, this week there were some issues with the distribution of the rewards. Although players walked over 50 kilometers, they only received the reward for 25 kilometers. They would have needed to walk significantly more than 50 kilometers to receive those rewards.
This is the problem with weekly rewards
What players report: On Reddit, some players report this error. For example, “Kevin50n3” shows a screenshot of his 58 kilometers that he walked. However, he only receives the rewards for 25 kilometers, as he suddenly appeared to have walked under 50 kilometers.

Thus, he was cheated out of 10 kilometers and only receives the smaller reward, even though he walked the correct number of kilometers. He would have needed to walk at least 60 kilometers to receive the better reward.
Other players affected: However, the Reddit user is not alone. Over 700 people have already agreed and shared the trainer’s problem. One user writes:
I have the same problem. Adventure Sync shows me 57.8 km, but I am rewarded for only 51.3 km. Luckily, I was still over 50 kilometers.

The problem is not an isolated case: Players repeatedly report issues with Adventure Sync. However, not as many players were often affected. Here, it seems to have impacted a very large portion of the player base. This is particularly frustrating for players who have been deprived of their rewards, even though they walked the correct number of kilometers.
Another change is also driving players crazy: