Does Cpanel change mysql user priviledge automatcially by some rules?

Hi,

I am using Cpanel. One Cpanel account is backup. I use it to backup my database.

Under mysql, I gave this account ( backup ) many priviledges. But when the backup script ran, error said that backup account can not 'lock table'.

I gave "lock table' priviledge again and run the script, it is ok.

But after a while, when the script ran autmatically on daily basis, it lost the 'lock table' priviledge again.
I wonder if Cpanel is messing me up? What can I do about it? anyone knows?


James