Thanks for the help here, Cathal_S.
loumira, are you pertaining to the glare and reflections during night vision? If yes, then this issue is caused by reflections of the IR LEDs (used for Night Vision) from a nearby surface. We suggest you to change the positioning of the Nest Camera to ensure the entire front of the camera is unobstructed. You can also move the Nest Camera to another room or area and try using the Zoom and Enhance option to exclude the reflection from the camera's field of view.
For more info, please check this support website article.