When shortening a folder, the content's playback will not be cut at the folder's end. In a folder, a MIDI note or an audio file will be played in whole, even if it exceeds the folder length. This only affects MIDI notes or audio files that start within the folder limits.
There are two workarounds, cutting the content at the folder's end or cutting the folder.
Workaround 1: Cut the content at the folder's end
Workaround 2 (applicable only to folders which contain only audio files): Cut the folder instead of resizing it.