when one of the node leave the cluster because of poweroff or network failed issues, the node return finally.
but the hadr status will not be right at some conditions.
use lssam to check it .it may looks like below.
use this cmd to swith the resource and node to right status.
resetrsrc -s “Name = ‘db2_bpminst_bpminst_PDWDB-rs’ AND NodeNameList = {‘ipas-pvm-017-048’}” IBM.Application
then ,the hadr status should be like this.