At PetaPixel, Jeremy Gray sums up his coverage of the increasing prevalence of SanDisk portable SSD failures with:
For now, anyone using a SanDisk or WD portable SSD should tread with extreme caution and ensure that their data is adequately backed up. Everyone else should ignore the continued deep discounts. Until PetaPixel feels as though the situation has been dealt with, it cannot recommend SanDisk portable SSDs.
I have no personal experience with these products, but the reports are coming in from enough independent sources that I encourage anyone using a SanDisk portable SSD to be extra careful about backups and consider a replacement.