Why does my computer turn off when I unplug my charger cord from the wall?

Issue: Customer that has a few carts w/ the HF-1800 and all of the carts have the same devices and same make/models. On one of the carts, every once in a while, when they unplug from the wall, the CPU will shut off. I was guessing that either the computer was more sensitive to the delay than their other machines or this inverter happens to have a longer delay than the other inverters. So I told them to swap the computer from a �good� cart with this computer from the �bad� cart. The result was that the behavior remained with the cart so I�m suspecting a slow inverter switch. Background Information: There is a delay on the automatic transfer switch when �shorepower� is broken, before the battery power/invert mode is made. Whether this delay impacts load operation, usually depends on the load. The elapsed time between break/make varies depending on the transfer switch and to a lesser extent, on some other factors. Sometimes, there's enough capacitance in the CPU that it can maintain through the hiccup, but if the HF takes over during a downward slope of the wave, and the plug had just completed a down slope and was rising in voltage, that makes the available power gap seem longer to the load then if the shoe and inverter happen to both be on peak voltage at disconnect and connect. Four options that come to mind: Inverters have a range of transfer switch delay time and this inverter is on the high end. While this is a nuisance, it is infrequent and perhaps they can accept it. We RMA the HF1800 and replace it with a new one with the hope that the new one has a faster switch. We RMA the HF1800 for an HFS series that has a faster switch (10ms vs 30ms). The install a UPS power strip (roughly $50) between the inverter and the computer (not sure we�d pay for this or assume support responsibility). https://www.walmart.com/ip/APC-650VA-Back-UPS/54695291