A:Answer If you're referring to the long nichrome elements lining parellel on the top and bottom, then yes. those elements turn off once desired specified temp has been reached based on the nob settings you've selected. Nothing to worry for.
now, if the Indicator Light (which is usually bright RED) located above the buttons turns off spontaneously that would indicate the toaster has a malfunction, the light is to indicate the oven is operating, if it's turning off randomly that's an issue.