Two automatic features respond to different inputs
Samsung describes Brightness Optimization as reacting to ambient light and Motion Lighting as reacting to screen movement. A picture becoming brighter or darker can therefore involve an automatic TV control rather than a changed stream.
Note whether the change follows room lighting, on-screen movement or a switch between programmes. This observation chooses the relevant comparison and avoids treating every variation as an HDR fault.
Compare one control
Use the TV’s documented Power and Energy Saving route for the model. Samsung notes that some controls are unavailable when Adaptive Picture is enabled. Check the current state rather than assuming a greyed option needs an app update.
Keep one familiar passage and the room lighting stable while comparing a relevant automatic control. Then change the room-light condition separately if that is the suspected trigger.
Preserve a comfortable viewing choice
If the comparison identifies a feature the household dislikes, choose the supported setting that suits the room. Do not describe that preference as a universal calibration or guaranteed energy saving.
For help, record the feature state, picture mode and repeatable trigger. This separates an intentional television response from an unresolved source or hardware issue.
Questions answered
Are Brightness Optimization and Motion Lighting identical?
No. Samsung describes different triggers for them.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.