I'm running QGIS 3.12.2 (current)
I loaded about 10 rasters (satellite imagery) into a new project and digitized some polygons on each. I saved the project. When I reopened the project, the rasters don't display, and appear to have lost their geolocation.
The world map does display, as do the vector files I originally created.
When I zoom to a single raster layer, the layer displays The coordinate window changes from lat/lon to some long, integer z/y (perhaps easting/northing?) Also, when I zoom, the world map and vector files disappear.
If I zoom to the world map in the project and try adding a new image raster layer, it does not display either (even if checked on and at the top of the layer list.
However, if I start a new project, load the world map, and then the same image file, it displays correctly.
What gives? Any ideas?