LACP with Gigabit interfaces - Best Practices for Auto-Negotiating Speed?

I understand that most manufacturers recommend use of auto-negotiation with gigabit links as best practice, but today we got burned. A member of an LACP aggregate failed to auto-negotiate properly, and each end of the link handled this differently, causing the entire aggregate to flap. I cannot find any documentation to see if what happened is expected according to the standards, or if we might have a device that is not functioning in compliance with the standards (in which case we can open a support case with the offending vendor).

Two questions:

• Is there a documented best practice for LACP that recommends avoiding link speed auto-negotiation?
• Does the LACP standard define some specific logic that a device must use when detecting and responding to a speed mismatch between port members? (For example: Is it the fastest link that wins? Is it the first link bundled that wins? Is it some other criteria?)

The Details

4 x1Gbps links bundled in a LACP etherchannel between a NetApp and a Cisco IOS switch. Ports configured for auto speed/duplex on each side.

1. A power failure occurred and devices power cycled.
2. One of the ports auto-negotiated to 100Mbps (consider this a separate issue, root cause of this is not the primary concern, but this triggered the more concerning issue).
3. Cisco Switch detected that this 1 port (100Mbps) was not compatible with the other ports (1000Mbps), and removed it from the bundle. This seems like the ideal behavior (but is it standard?).
4. NetApp detected that the other 3 ports (1000Mbps) were not compatible with the one port (100Mbps) and removed all 3 of them fro the bundle. This seems like the opposite of the ideal behavior (but did they violate standard?)
5. This lead to flapping back and forth again and again with the netapp repeatedly removing and re-adding the 3 ports, and the switch repeatedly removing and re-adding the 1 port.
6. After physically disconnecting and reconnecting the link that negotiated to 100Mbps, it successfully auto-negotiated back to 1000Mbps and the connection was once again stable. We are replacing the cable in-case the cable is faulty and caused the failed auto-negotiation, but my concern is that such a failed auto-negotiation can fail an entire bundle like this.