Due to the characteristics of wireless technology, the sound played on the WF-1000X headphones could be slightly delayed compared to the sound or media output of the device you're using.
Music and other regular audio files such as podcasts and audiobooks will not be compromised because of this characteristic, and your listening experience will therefore not be affected in the slightest. However, when viewing movies or playing games, images and sound could possibly be misaligned because of this natural delay. Nevertheless, your TV, smartphone and headphones are working properly as intended.
For more information, please check the instruction manual provided with your headphones.