Finding the cause of a distracting loop seam

[LucasGaks]

For an exploration prototype, I am preparing a short music loop for one room. After several repeats, the boundary starts drawing attention away from the scene. I need to distinguish a poor loop boundary from a sound already present in the export. A comparison between two crossfade lengths seems like a sensible starting point. I would keep the level and all other edits identical between versions. There is no dramatic change in the room at the repeat point, so the music should not imply one. I would listen to several cycles in context, then inspect the boundary separately, keeping notes about exactly when the interruption becomes apparent. A page about remove suno artifacts came up during my search for another possible check. Without a comparison, I cannot tell whether processing would affect the boundary usefully. A continuous mood matters more here than making every isolated moment polished. Which checks would you make before changing the exported audio itself?