In the bucket status dashboard you can see why the fixup task per bucket is in pending.
One of the reason is that, it was not roll to warm yet.
Did you put the cluster to maintenance mode and gracefully shutdown the indexer?
You have fixed up task because 1 indexer is being shutdown and it stops sending heartbeat to the Cluster master. This causes the master to detect the loss and initiate remedial action and will replace bucket copies on a downed peer by coordinating the activities to other peers.