Hello!
p2p is allowed on pool 2 but it can be really used only by those programs that let you configure which IP address to announce (non existing, as far as we know). More in general, pool 2 is not suitable for any program which announces itself autonomously. In AirVPN infrastructure, the VPN traffic reaches the Internet through one exit IP address, but "pool 2" is the set of ports of another IP address (let's name it exit IP address 2, in brief exit 2). If a program receives an unsolicited incoming packet from the Internet through exit 2, it will reply properly. This happens whenever you advertise on your own how to reach your service (a web or FTP server, a game server, and so on).
However, with p2p programs, it's the program itself which must advertise. DHT or a tracker will record the address they receive the advertisement (of the port etc.) from, and they will say to other peers that your p2p program is reachable on exit 1, with its pool 1 ports; however, if you have remotely forwarded a pool 2 port, peers would never be able to reach your program, because they would send packets to a port of another IP address (exit 1, the address recorded by DHT and/or trackers). The problem could be resolved by manual setting (see for example https://userpages.umbc.edu/~hamilton/btclientconfig.html#BTConfig ) when you need to seed only - additional tests are required.
This is an important limitation that might be overcome in the future, for example by letting the user pick which exit IP address its traffic must go to the Internet through. In the meantime, by using pool 2 (and when necessary additional pools) for anything different from p2p and crypto wallets, port exhaustion problem is solved (in most cases only 1 forwarded port is needed for p2p).
Kind regards