The deleted miner reappears in the miner list.

This is normal. When you delete an online miner, it will reappear in the list after approximately one minute. Similarly, if you delete an offline miner, it will reappear in the list once the miner comes back online.
If you wish to remove a miner from your account, you can do so by deleting it in Goldshell Zone/Hub platform and also deleting the corresponding key in the miner dashboard while disabling cloud control.