Switch server cause some containers lose

Before, rancher/server run at A. Host B is a agent point to A
i run a new rancher/server at C.
Then, run register script on B , make B point to C
Now ,i found B lose some containers (not the rancher-self services)
In B, “docker ps -a” still not find them.
Could someone tell me where are the containers.
My english is poor