Thank you for posting. Your concern is best answered by our motherboard support group. I'll move this post to them.
Is there any way to reproduce step by step this problem? Please open CMD and ping to 127.0.0.1 –t and provide all results with images.
As part of the troubleshooting steps, try rolling back to previous BIOS version.
I have been fiddling on with various BIOS updates to see if I can reproduce this.
Initially the 3 machines I tried on were at BIOS 53 and I updated straight to 67.
BIOS versions available from Intel website:
52, 53, 54, 55, 57, 60, 61, 62, 64, 65, 66, 67.
53 -> 67 = flapping.
67 -> 53 blacklisted.
67 -> 54 failed.
67 -> 55 OK and no flapping.
55 -> 57 OK and no flapping.
57 -> 60 OK and no flapping.
60 -> 61 OK and no flapping.
61 -> 62 OK and no flapping.
62 -> 64 OK and no flapping.
64 -> 65 OK and no flapping.
65 -> 66 OK and no flapping.
66 -> 67 OK and no flapping.
67 -> 55 -> 67 OK and no flapping.
I have left the Windows driver untouched during all of this.
These BIOS updates were all done via the Windows .exe file.
I have another DQ67SW on the shelf so may start a fresh with that one next - it is still BIOS 53.
The CMD prompt ping seems to result in the same response every time - even on a flapping board. Just to restate - the flapping only happens when the PC is not running and Windows has been shutdown, but still powered - so it can be WoL. I have not tried sleep/hibernate.
I'll fiddle on with various other combinations - but any pointers at this stage would be good.
These are definitely great steps and great information. So you are saying it is working fine now, right?
Upon further investigation - one the BIOS updates has disabled the Intel AMT. In the BIOS it reports firmware version 0.0.0.0
I have tried various options to get it reinstated - but no luck yet. Any suggestions?
In Windows device manager the Intel AMT SOL driver has a yellow triangle with 'cannot start (code 10)'.
I suspect once this is resolved the flapping will return.
I'll try and spend more time on it next week.
The other 2 boards are still flapping. If I cannot resolve this board I'll start again on another and watch it more carefully at each BIOS update.