[Samsung Galaxy Note 8 Questions and Answers] Kamikaze_Ice:
If the latter was true, why not simply remove the option to begin with? I don't think Samsung would make it a "one time only" option either, but that's my opinion.

There must be something to this, at least for those who did have the OEM Unlock option but lost it for some reason.

Where/Who was the device purchased from?

Did the package advertised match what you really got?

Did the seller do something for you, like region unlocking or changing the language for you or otherwise opened the package before shipping it to you?

Where was the device made?

Which factory was it built/assembled in?

What production cycle/run for each component? (This is sort of like CPU binning, where some runs are notably better or worse than most other runs) **I wouldn't have any idea where or how to find this information without CPU-z lol)

Was a complete backup made before doing anything? State of OEM Unlock option? Like the default setting, was it changed before creating said backup or afterwards?

If OEM Unlock is/was present in the options, was on/off behavior verified before flashing anything?

Did OEM Unlock reset after rebooting? Two boots? What about entering then leaving stock recovery?

Does root effect this in any way?

What was flashed?

Where did it come from?

Were files verified the device to be flashed? (like, no sneaky renamed or misnamed files?)

How did you flash?

Was any of the above done with a fresh device? Fresh as in the device has NEVER had a SIM in it?

When was a SIM first used?

Flashing with and without a SIM, any changes?

...

I'll stop here, I think everyone get's the idea. Perhaps we could draw conclusions by knowing this kind of information. Or not.

I know Samsung has been known to be a little jerk to devs in the past. I've never had a reason to read anything outside of HTC Inspire & One (m8) threads so I have no idea if this is still true (past ex: lack of GPL compliance, altered source code, erroneous settings, AOSP compatibility/superbricks, etc).

I don't suppose this could be as simple as adding the option into the menu again. I have no clue where the option would be in this filesystem. A quick search pointed me to /data/data/com.android.providers.settings/databases/settings.db which is apparently for versions before Marshmallow (Lollipop and earlier).

Sorry I'm not much help. I was so close to getting one from never-msrp (ebay), and canceled because I said screw it I want Deep Sea Blue with 256GB internal storage so I can stop converting my FLAC rips into mp3s (I'm an artsy fartsy audiophile, so Spen + my massive music collection = must have. I cycle 10k songs every few months.) Should have my Korean Note 8 sometime next week (from same seller as Kalm_Traveler). I don't expect to have OEM Unlock issues, but I'm still anxious about it.

Silly ideas:

Could this be similar to region locking? Like, get the device all squared away with your provider (IEMI? Provisioning? I've never had to do this so I have no clue what this really entails but I think anyone here would know what I'm trying to say), and then do the stupid 5-minute call thing to see if this does anything (reboot first? reboot to recovery? adb unlock work?).

What happens if you use a different SIM? Different carrier SIM? No SIM? What about flashing/rooting along with those?

Magnet triggers, like on Samsung flip cases, and/or DeX mode. Highly unlikely, but without proof can't say Samsung could tie either of them into triggering a secure rom/flash/whatever check making flashes fail.

Try saying Betelgeuse three times might work.

Like I said, silly 'innit? :P