Limit of n reached for LEASES quota in NETWORK for user


I have several users (Students) into Opennebula. I’ve set some quotes for them regarding disk, cpu, etc. They have a quota of 2 public IP for one network, and infinite for private network.

But something strange happens with a user who can’t create new VM because of this:

limit of 2 reached for LEASES quota in NETWORK with ID: 0.

But this user only have one VM running with one public IP.

Worst thing is that in his profile, I can see: Network Leases: 2/2. (0 remaining).

Where is the problem? Is there a public IP not used but Opennebula thinks is in use?