Can someone explain this and why all my shares are fine but the blocks I find only do this when I'm solo mining on at pool.

[14:00:18] INFO  - Setting new difficulty: 6 (0.0234375)
[14:00:18] INFO  - Received new job #b7c3
[14:00:18] INFO  - 340/2 Rejected : diff=0.127551, reason: Invalid job id
[14:00:18] INFO  - 341/2 Accepted : diff=0.0294112 : 22.56MH/s
[14:00:18] INFO  - 342/2 Accepted : diff=0.0339268 : 22.56MH/s
[14:00:20] INFO  - 343/2 Accepted : diff=0.063726 : 22.56MH/s


Crap well the line above was where i found block 2 but why the invalid job id just for the blocks?