Buoys that mark only the left or right side of the channel will never exhibit which characteristic of a light?

Buoys that specifically indicate the left or right side of a channel are designed to provide clear, straightforward navigation guidance. These are typically lateral markers, and their lights are usually kept simple to ensure that mariners can easily distinguish between port and starboard sides.

The characteristic of "composite group flashing" involves a complex light pattern that can consist of multiple flashes of varying durations and colors, which serves to give a unique signal to help identify a specific buoy or navigational aid. This complexity is not aligned with the purpose of lateral buoys, whose primary function is to aid navigation through straightforward and easily recognizable signals.

In contrast, flashing, quick flashing, and equal interval (isophase) lights can be found on various navigational aids, including lateral buoys. These lighting characteristics provide unique identifiers while maintaining simplicity, which is crucial for effective navigation. Thus, the presence of intricate patterns such as composite group flashing deviates from the straightforward purpose of lateral buoys, which is to mark the sides of a channel.