Selection tool, bounding box
Square did not fill with the fill color I selected. The objects are all pixelated and not clear. Bounding boxes keep disappearing. Objects moving back to previous positions.
Illustrator can display artwork in Preview mode and Outline mode — with only lines edges drawn. You can switch between this modes with Cmd/Ctrl+Y hotkey or via View > GPU/CPU Preview / Outline command.
You seem to accidentally have pressed Ctrl+Y and went to Outline mode.
You can press it again or do the same command via View > GPU Preview (or CPU, whatever)