LTM has lost sticky persistence after one node went down

Persistence logic would vary based on the connection type. If its an active existing connection and the pool member is down, then LB algorithm wouldn't be triggered here. This is where we use the action on service down concept.

But if the connection is close, and the following request comes from the same source with the pool member down,then LB algorithm would be applied.

Reset your persistence stats and see whats happening. LB algorithm would choose just 1 member, it cannot jump between 7 and 10.