So, can they?
In theory, yes. But the advantage they may obtain would be both short and shortlived.
Several blackjack card-counting gurus, such as Elliot Jacobson, have spoken about intrinsic "latency" with CSMs. This means there is a drag or delay of the cards used in the last round before they are back into the shuffle-mix. Since the cards for the next round are already prepared, the cards used in the previous round are not inclusive in the total cards remaining in the deck, therefore the counter can tally them up and come-up with a count estimation of a small advantage.
"Small" because there is never more than one round played in any given situation. Unless each player and the dealer at a filled 7-spot table hit several times and use almost a full deck of cards, there would not be a true positive count of any significance.
So in spite of the theory that CSMs are vulnerable to card counters, in practice it is a waste of time.
An important thing to note, however, is that CSMs are not completely taking over land-based casinos' blackjack tables. They are expensive for casinos to buy, lease and maintain, and many valued non-counting customers simply don't like them and refuse to play at tables that use them.
So there are still plenty of tables worldwide for card-counters looking to avoid continuous shuffling machines.