I was playing against the online version of Shredder on the hard setting, and after this weird opening phase I went ahead with a queen trade, but weirdly Shredder didn't take my queen. Is this just a glitch, or is there some feasible strategy behind this move? The pawns aren't really a threat to my king; I'm not locked in and there is no support for the attack.
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "Shredder"]
[Black "Me"]
[Result "?"]
[fen ""]
[Startply "1"]
1. d4 d5 2. c4 dxc4 3. e4 Nf6 4. e5 Ne4 5. f3 Qd5 6. fxe4 Qd5xe4 7. Ne2 Bg4 8. Nc3 Qc6 9. d5 Qc5 10. Qd4 Qc5xd4 11. e6?