Unexpected gmirror behavior: Is this a bug?

[Peter Steele]

> This only happens with ad4. If ad6 for example goes offline in the same way, when it is reinserted 
> it does not become the dominant drive and resync its data with the other drives. Rather its data 
> is overwritten with the data from the 3 member mirror, as you'd expect. 
> looks like very strange bug. many times i got drives disconnected and 
> always gmirror resynced 

If I just pull ad4 and then reinsert it without doing a reboot, everything works fine. The problem occurs when ad4 is pulled and then reinserted after the system is shutdown. When the system comes up, it doesn't get added back to the existing mirror but rather becomes the principal member of the mirror, using its old data. Not good.