SSD's have much more complicated firmwares than HDDs, there is so much more to go wrong. With using more layers, and having more features to assist in caching and wear leveling, things can definitely go wrong.
At the company I work for, we did extensive testing on SSD's years ago, after one brand failed us due to firmware bugs. This stuff is not hard to detect with a reasonable testing setup, if you're looking, especially if you have cooperation from the manufacturer, which reviewers typically have. It was a pet peave of mine when I used to read SSD reviews and all the reviewer would say about endurance is the marketing tarabytes written. I used to comment on reviews requesting them to actually test life exepctancy, or at least LOOK at the SMART data after all their testing, and get a gut feeling if it is ok or not. This would have caught this issue and it could have been presented either to Samsung to look at it, and hopefully fix it before it was released, or have a firmware ready to go soon after release. Or, reviewers could have given a warning to buyers.
Something to understand about life expectancy and "terabytes written". The spec that they advertise and gets repeated by most people and reviewers is NAND writes. And this is based on the NAND that was used in the product, it's well tested, how many writes can the NAND handle on average, mixed in with over provisioning, you have your terabytes written.
The problem is, that people (and probably some reviewers) expect that to be "OS bytes written", when you copy 1 TB to your disk, that's an OS write. Unfortunately, unless you look at the SMART data (you may need manufacturers help to understand how to decode it, or to get the the units they are storing in) and look at the NAND writes. you really have no idea how much you've written to the disk.
Your "1 TB" written, may actually be much greater than 1 TB NAND writes. Actually, now that I think about it, DRAMless cached models, it may even be greater than 2 TB, if they are copying it from some SLC mode NAND over to standard multi layer/3d NAND.
The difference between OS writes and NAND writes is called "write amplification", it's a known metric for SSD manufacturers, and different grade SSD's intended for different uses (consumer vs enterprise for example) will have acceptance of different write amplifications to be within spec. Thats why it's a faux pas to use a consumer grade drive in a NAS. Perhaps DRAMless SSD's have higher write amplifications due to caching, I don't know. But I do know that features like wear leveling and maintenance tasks will increase the write amplification, as the SSD maintains the data on the drive and pushes it around. This is all normal and expected, but if something is wrong with the firmware, things can easily go wrong, and write amplification can get out of control.
We should try to get a full dump of the SMART data, and see if samsung publishes it's SMART data documentation, and we'll probably find that NAND writes are actually right in line with the life expectancy that's being reported. If the workload is typical, then this is likely a firmware bug