This won't go away and in fact will likely just get worse over time. Unless you got this incredibly cheaply as a sub-standard item, you should definitely seek a refund. It appears a very common issue in Samsung TVs, as this Community web site shows. I would have hoped it would have been permanently fixed by now. I bought a Samsung UE55JS9000 for £1635 on 5th December 2015. I did not initially have this problem while I switched it off at the main power supply when not in use, but after three or four years I started leaving it on standby between uses as it improved integration with other devices. Soon after, this light bleed problem started. It might be coincidental timing, but I doubt it. From other sites, I have read that the cause is burn out of plastic strips at the edge of the screen, which I could understand may be more likely if the device is not fully powered off. I got to this level of detail after finding that Samsung no longer produced curved screen panels, but I quite like a curved screen. Definitely, this is not something I would recommend, but other users have suggested it is possible, that while disconnected from the main power supply, and with a screwdriver, you can remove the back of the screen and replace these plastic edge strips with similar, if you can source something. Thereafter, maybe do not leave the screen on standby, unless you are happy to repeat this process. I've not tried this myself yet, but I plan to, clearly at my own risk. The amount I paid for this television at the time was clearly top end, and in that range, products should not be failing even after many years of use. This appears to be very poor quality control. This exact issue has clearly been happening since at least 2015 - that's EIGHT years - surely past the length of a full product development life cycle, so again, Samsung, what are you doing to cause this still to happen, especially on higher end devices?
NB If you bought this in the UK, note that: The Consumer Rights Act 2015 makes it an implied term of the contract you have with the retailer that goods be as described, fit for purpose and of satisfactory quality.
As that is in breach of contract and you've owned the product between 6 months and 6 years, you are within your statutory rights to ask for it to be replaced or repaired
