This is still a problem in arena format.
I had the same problem of using K9-0tron to dredge, then select the 1 cost minion, but not draw it. As you can see a totally different card is drawn on the next turn that wasn’t even on the bottom with the previous 3 choices.
https://replays.firestoneapp.com/?reviewId=013bdbe4-2f1e-480c-9c24-0e3868b89197&turn=5&action=2
No matter how many times I read OPs post, I can’t deduce that their opponent did any shuffling. Lack of information gathering on their part somehow makes it sound like the OP was the one who didn’t understand something.