I am using ArcGIS 10.6. I have a .tif file and I created a mosaic dataset and added this .tif file to it. Then I published it to Portal and everything was working fine.
Then suddenly I started getting the check pattern in mosaic dataset. After doing a little research I came to knew that this is because there is some issue with the mosaic dataset. I then repaired it but issue was still there so I checked the source dataset (the original .tif file) and I came to knew that it is missing the spatial reference. I don't know how suddenly a working file loses its spatial reference.
I know the projection information and I can project but wanted to make sure why this happened