have you ever checked tha SMART values of the drives?
If there are SMART values, you can go and check the total bytes written. There are plenty of calculators in the www.
In case wear-out is the problem, you might want to chose more reliable drives as chewitt recommended. Samsung PM series or even Evo Pro. I use Micron 5300/5400. Or any other brand where you have the option of overprovisioning. The internal processes of SSDs are made very different depending on the manufacturer. TRIM and garbage collection as well as re-copying data. You might know, that - other than HDDs - SSDs aren't able to rewrite data blocks. A SSDs always has to delete the block before it can be written. This causes write overhead which hurts the overall endurance. Some manufactures are handling this better then others....
However, this might not be the case on streamed data. The more you stream sequentially the better it is in terms of endurance.
What Kingston model do you use? Are there TBW or DWPD (drive writes per day) values available? Quite often the entry level drives don't even mention these values....
e.g. a 128GB drive has 0% overprovisioning - so no room for re-copying data
120GB has around 7% overprovisioning - some room for re-copying data and internal processes.
...the more OP the more reliable is the drive. The more often you write the NAND the earlier it gets weared-out
hope this helps
maybe the kingston drives stucks with internal processes at a certain point and unplugging the power does cause a reset... kind of wild without knowing the wear-out level, but it could be the reason
never use entry level drives for valuable data