I had come across this bug before, but I thought it was just my imagination or something. I could have swore I had two of the same survey, but when I looked in my inventory, they were both gone.
I was able to replicate this bug in Western Skyrim, using two Woodworking surveys. Wood isn't a big deal so it would not have bothered me if one disappeared, so I tested my theory... sure enough, both surveys disappeared from my inventory as soon as I looted the first node.
I am not sure if this bug is universal. I also tried to see if it happened with a pair of Enchanting surveys in Bangkorai but they worked properly.
I simp for vampire lords and Glemyos Wildhorn