Check the enclosure before the slicer
Confirm the printer is enclosed, doors or panels are closed as intended, and the machine is not sitting in a direct HVAC draft. Give the printer and bed time to establish a stable environment before starting a large part.
Verify the first layer
Clean the build surface, verify the correct plate is selected, confirm first-layer height and inspect the actual contact area. Corner lift that begins early in the print often starts with weak adhesion rather than a temperature problem higher in the model.
Reduce the thermal gradient
Large, dense parts store and release more heat. Use the filament manufacturer's recommended bed and enclosure strategy, avoid excessive part cooling and consider a brim or geometry changes where shrinkage forces are concentrated.
Look at geometry and orientation
Long straight walls, sharp corners and large flat footprints can concentrate shrinkage stress. Radii, rounded corners, ribs, split parts or a different orientation can sometimes solve a problem that slicer tuning cannot.
Change one variable and document it
Once the basics are controlled, change one variable at a time. Record the filament, temperatures, cooling, speed, adhesion method and result so the next print adds information instead of restarting the experiment.