PKI Multiple Samples start to expose Private Keys?
There's a wide gap between plaintext recovery and key recovery.  Of course, what is of interest to users is the confidenitality of their plaintext, but if an attacker can merely recover a single plaintext (which might happen outside the domain of crypto if the user just leaves it on the tube on their way to work!), that doesn't mean they can recover the next one—while if they can recover the key, they now have all the power of the legitimate user.
Public-key encryption is necessarily randomized so that if you send the same message to three people, or even send the same message to the same person three times, I still can't tell that just by looking at the ciphertexts without breaking the crypto.