Are youth players poachable?

I'm running a bit of a youth academy challenge with a lower league Italian team (with edited youth coaching/recruiting settings), and I'm having trouble with teams "signing" some of my youth players that are under contract. For instance, I have a 16 year old in my U19 team with a large amount of potential, but who was on a youth contract for the next several years. I had received a large number of transfer bids for him, and had managed to fend those off, but Sampdoria comes in and straightaway offers him a contract, which he signs. Is this legal? Is this a bug? I'm not getting any notifications that he's eligible for a pro contract, but Sampdoria comes straight in and poaches a player that's on contract for the next three years to me. Can someone explain?

When a player is on a youth contract they can be poached, But if you offer them a full time contract and they agree to sign it then they cannot be poached,they will remain on a youth contract until they turn 17 but can't be approached by other clubs.

It is down to you to sort this out with the ones you think are worth keeping

So I'd pretty much have to offer pre-contract deals to *any* youth player who could conceivably be poached? Dumb question then: why are all the other teams offering to buy him rather than trying to sign him? Seems like they'd all just try to sign him.

Because he will have a set fee if they approach him, Where as you may sell for lower. If poached they have to pay you coaching fees and compensation. You may just settle for less in cash immediately

I have had scouts tell me £1m to sign a player, And £2.5m if i approach him to poach, So sometimes the bid is the best way.

They could have been trying to get him for less money than they'd have to pay if they offered him contract.