Compare the receiving displays by identity
Record the model of the original screen and the second television or monitor. Note the observed resolution and orientation on each, plus the Galaxy and One UI version. Compare the same connection method if possible so that a new adapter or wireless route does not silently become another variable.
Samsung’s current FAQ explicitly describes per-display settings in One UI 8. It says the settings used for one display can differ when another is connected, while reconnecting the same display retains its own arrangement. That is a narrower behaviour than a device forgetting every preference.
Inspect the connected display’s controls
Samsung places the relevant settings under Connected devices, Samsung DeX, Connected display in its One UI 8 description. Use the current screen’s supported options and confirm the intended orientation or resolution there. Do not infer that a saved value from another display must be available on this one.
Keep the physical screen’s capabilities with the selected output. A rotated desktop or changed resolution is a display arrangement; it does not establish that the source programme has a different encoded resolution or aspect ratio. Record those media characteristics separately if they are the actual concern.
Retest the original screen once
Reconnect the original display and inspect whether its previous settings return. This comparison directly addresses the documented per-display behaviour. If the same display repeatedly loses its own saved arrangement, retain that as a different finding rather than treating a second screen’s settings as proof.
For help, provide both display models, Galaxy software, connection methods and the values seen on first connection and reconnection. A clear report can distinguish expected separate profiles, a display-specific limitation and a genuine retention problem. It avoids repeatedly changing a working home-TV arrangement merely because a different screen starts with different output settings.