Bug with 10.8.2 and Tbolt to FW adapter

I believe I have discovered a bug concerning Mountain Lion and the Thunderbolt to Firewire Adapter.

Setup: 2011 iMac 27" 10.8.2 + TB to FW Adapter with Seagate FW800 Drives attached via this adapter.

With Energy Settings set to Computer Never Sleep and Screen Sleep after 10 minutes and Wake up Drives on Network Access checked.. and Password required immediately upon screen sleep checked in Security

When Screen goes to Sleep automatically as per the Energy Saver Settings.. most of the time the TB to FW adapter goes to sleep... or slows down disk acess dramatically causing the drive to error (Usually -36) causing activities like file transfers to crash out..

I have tested this out on two different iMac and ML systems with two different TB to FW adapters with the same results..

If I set Screen to Never Sleep then the issue does not arise... I have tested this out using large 2TB to 2TB drive, multi file transfers and no problems..

As soon as i set Screen to Sleep and perform the same 2TB to 2TB multi file transfers the issue occurs approximately 80% of the time, as soon as i wake up the screen from sleep and after I unlock using my password.

The Disk Activity monitor clearly shows a substantial slow down of disk I/O for the rare occasions the file transwers do not scrash out.. from the moment the screen went to sleep until i woke it up again upon which the I/O rate returns to normal.

Note: I did not see this behavour in any previous OS version, such as Leo SL or Lion... Just Mountain Lion. I cannot say if this is a bug that has arisen in ML prior to 10.8.2 as I have only installed ML 10.8.2 (with supplementary updates)

Can anyone else confirm?

Cheers..

Update: Could it be that because the TB port is also used for Video, that due to some bug somewhere, this is why this is now occuring?

Message was edited by: The Art Of Sound : Suggestion regarding possible reasoning to this bug