Sometimes, when a reference is attached, it does not display, cannot be found in the master file view, or only displays partially. Also, it may behave differently when zooming, elements disappear and reappear when zooming in and out. When opened directly or exchanging out to the reference, the elements are all correctly displayed
One reason why this might occur is because, occasionally, (either intentionally or unintentionally) a 2D Model is attached to a 3D Sheet Model and there is a Z value assigned to the reference (to which the user was unaware). If this Z value is too large, the reference may not display. Note: This could also occur when attaching a 2D Model to a 3D Design Model.
Elements on reference levels not displayed in master file
How to turn off the display when attaching a reference