Problem LACP

We have a virtual chassis with three 6860. We have a link between the switch and one 6900 router. The problem is with the link aggregate LACP. The link combine the 1/1/28 port and the 3/1/52 port at the switch. My problem is when we lost the link aggregate because one power off at the router for example, the aggregate on the 1/1/28 remains down when recovers the power at the router. The other one, 3/1/52 is up. The switch ID 1 recognize the Mgbic (1 Gb SX) but the laser is off. I have to reboot the virtual chassis to recover the link at the LACP.

We have changed the switch ID 1, the fiber and the Gbic and is the same problem.

Any of these in use: UDLD or ERP?

What is the actor admin key of your lacp linkagg (both sides)

Any trap or interface entry in swlog?

Do you have phisically the possibility to combine ports within the ID1 1/1/X? if not Pls create eSR. Thank you