The computer is programmed "knowing" how much current each particular circuit is SUPPOSED to draw. A higher-wattage bulb is likely being interpreted as a malfunction. When BMW first came out with the original "Flying Brick" K-bikes, a lot of owners who installed headlight modulators and flashing brake lights found themselves inexplicably stranded when their bikes shut down for apparently no reason.
Ever since the CAN-BUS bikes came out, Aerostich has been posting warnings to people who bought their heated jacket liners to have another accessory socket installed that is wired directly to the battery via fused relay, bypassing the CAN-BUS system altogether. The jacket draws enough current that the CAN-BUS detects it as a malfunction and shuts the bike down. Their electric vests and "Warm Bibs" are CAN-BUS compatible.
And here we were thinking all these advanced electronics were here to make our lives easier?