Weird behavior after server reboot

Hi all,

I am currently running elasticsearch 7.2 on an ubuntu server.

And I faced some weird behavior that I don't know what to do.

Here is some background
I change the default data path to a newly added hard drive.
And everything works fine.

And here is what happened.

old data: the old data located in the default data path before I change the path.
new data: the data I modified after I change the path.
updated data: the data I modified after the data disappear.

action: update from 7.1.1 to 7.2 & reboot
event: the whole elaticsearh folder in the new hard drive is gone.
data in the folder: nothing.

action: rsync the old data to the new folder
data in the folder: old data.

action: update the data
data in the folder: updated data

action: reboot
event: updated data is gone and the data in the folder is back to old data
data in the folder: old data

But after the I reboot a few times but there is no data lost again.

I am very confused so any suggestions will be welcomed.