there are lots of Samsung 128 layer NAND failure reports on the internet, and new cases are still coming in. (simply google "870 EVO failure") At this point I don't think anyone can argue anymore that those reports are just bunch of anecdotal cases.
However though, considering the fact that Samsung has the biggest market share, the failure rate can't be as big as, say, the "Seagate 3TB" crisis back in 2013 - in which case the issue must have been surfaced in a much bigger/louder way.
I am trying to say, even if we assume someone's 18 970 EVO plus drives were all 128 layer version in question, 18 samples are still too little to disprove anything.
I wasn't following 840 EVO planar TLC issues but the same pattern must be applicable - problem existed but the use cases that were actually affected by the problem must have been a small fraction of the entire volume which was manageable by Samsung.