When using the interface to mange public keys, duplicate keys are created and propagated among users.
1 key per user
First user has 1 key,
Second user has 2 key (his and first user)
Third user has 3 keys (his and the previous user)
and so on.
How to reproduce.
Create user A
Create user B
Select user A and create a public key for him using the +Add button
Close the "Authorized public keys for A" window
Select user B and open his keys.
User B display having the key created for user A.
However, when looking at the authorized_keys files, only user A has a key definied
Create a public key for user B using the +Add button
Upon saving, user B now display having two public keys, his and the one from user A.
However, both authorized_keys files show having their respective created key.
When clicking Apply in user B, both keys get saved in his authorized_keys.
Now user B has user A and his public key in his authorized_keys