If the array is exposed to a bright source, a remnant becomes visible. The amplitude of the remnant and the time it lasts depend on the brightness of the source. In broad band imaging, these remnants are not a problem as they are much fainter than the background. However, in spectroscopy, they are a nuisance, and, by Murphy's law, they are bound to land on your spectrum. We ask astronomers to check the brightness of their sources and in case where there are bright sources, we will arrange the schedule so that these sources are observed at the end of the night. However, there is little we can do if the acquisition image contains a bright source.