Shortly after him being signed I alluded to that on this same thread.
Guimarães signs a young lower tier unknown player --> Player scores a few goals in obscure pre-season games --> Jorge Mendes becomes player's agent, owing 30% of his pass --> Player signs a 9 million euro clause with Guimarães --> Such clause is widely publicised in newspapers along with unsourced rumours that Spanish giants have an eye on him --> Player is switfly bought by United apparently without much negotiation involved, as his clause was paid fully
These are facts, below is speculation.
It seems to me you lot bit the bait. Mendes and Guimarães cashed big on the rumours themselves probably started circulating, as it will be evident to anyone that knows how Portuguese football newspapers work.
With all that is known about Bebe by now it seems to me rather plausible that it was the above that happened, at least more plausible than a move based on a professional scout with thorough info on the player. If it was the latter, I think the transfer would have happened on a different timing and by different values.
If it was as I thought it was a childish mistake by one of the most successful and professional sports organizations in the world. One mistake, that's just it, I don't think it's reason for alarm. It happens, and someone learned something on the process. And well, it's still early, the future may even show it wasn't such a big mistake, though I doubt it.