When loading PostGIS rasters (through the brower or via DBmanager) from my database into QGIS (LTR versions on both MacOS (Big Sur) and Windows 10), these fail to render. Either nothing shows up, or a band is shown covering most of the UTM zone in which the raster is positioned (see image below. In this case, the original raster covers less than a square kilometer).
In QGIS 3.10 everything works perfectly. In QGIS versions after that, despite the rasters being listed in the layers' panel, nothing is being visualised (or I get the odd error below).