You may have to install the following updates two times to fully update Surface Pro Model 1796 or Surface Pro with LTE Advanced:
This issue occurs because the UEFI firmware update in these packages has the following prerequisite requirement:
Surface Pro (Model 1796)–Surface System Aggregator Firmware (233.2099.256.0) or a later version, released only on Windows Update on February 13, 2018
Surface Pro with LTE Advanced (Model 1807) –Surface System Aggregator Firmware (233.2102.1.0) or a later version, released only on Windows Update on February 13, 2018
In the first installation, the Surface driver and firmware pack installer MSI package installs the prerequisite and then prompts you to restart. Then, you must run the installation again to update the rest of the drivers and firmware.
For more information, see Updates for Surface Pro 4 (12 April 2018).