@PipMc 

What's the model of your camera? 

Please be sure to check for any conflicting settings. For example, motion detection can detect all types of movement. If the detection area is set to all, then any type of movement will trigger the motion detection. Line crossing detection does not have the concept of activity zones, it will trigger as soon as movement is detected crossing the configured line, regardless of the type of movement.

You can share your detection settings here, we can help you take a look. Upload the pictures to your cloud drive or the shared album, then send a link here.