@MarioC Poweramp plays all the aac files with the "issues" as previously provided by the users. There is no "universal" standard for aac files (which is not a container but a sequence of the raw aac packets, where AAC stands for the codec), so this is implemented "ad-hoc" in players. Poweramp aac support is based on modified FFMpeg and TagLib, with the fixes for the mentioned above user provided/test files.
From your brief description, longer file may not be fully played due to some non-audio content in the middle (e.g. parts of video stream, meta info such as tags/album art in the middle of song, etc). But that can be only investigated when the failing file is available on hands.
Thanks!