Hyper-V Failover Cluster - VM's from a Host A migrated to Host B after the shutdown of Host A but it restarted the VM's and not retain the current state

Hi Team,

We have a Hyper-V Failover Cluster with the below setup:

Host A

Host B

Host C

Host D

Scenarios:

1. During the shutdown of Host A, the some VM's migrated to Host B successfully

2. Some VM's migrated but it restarted and not retained to current State

Can we ask if what's the possible cause of the migration issues? Thanks.