This effect is caused because CD Architect is emulating the behavior of commercial CD players. All commercial CD players mute the audio when they seek. They then un-mute (fade up) the audio when they start playing. This is done to prevent clicking and popping during seeking. Some CD players take as long as 300 milliseconds to un-mute the audio. If you place your audio too closely to the start of a track, you run the risk of it being cut off by un-mute time on certain CD players. Car CD players tend to have particularly long un-mute times. The un-mute time that CD Architect uses can be set in the Preview page of Preferences.