After making your changes to a SKU in the Admin Portal, go back to the design in which the SKU is loaded, go to the Production Tab and select Settings in the toolbar.

In the lefthand panel, select Refresh Cache.

In the window that opens up, remain on the SKU Cache tab to see the SKU(s) for which the changes were made.

To see which value has changed for a particular SKU, select the Details button against that SKU's name.

You can close that window and select Continue to load the changes.

Load the SKU into the design. If already loaded, delete and re-add the SKU to see the updated version.