I would try changing some paramaters and see if it still occurs.
Try changing these settings back and forth and see if that fixes it.
hdparm -d1 -u1 -m16 -c3 /dev/hd<X>
Speeding up Linux Using hdparm
Not mentioned in the article:
UDMA 33/66/100. Add the -X option, and then this number i.e. (-X 69)
-X 33 ====> Multiword DMA
-X 66 ====> ATA-33 (UDMA2)
-X 68 ====> ATA-66 (UDMA4)
-X 69 ====> ATA-100 (UDMA 5)