The problem was that Curve2D is mathematically very strict with tangents. At the ends of curves (or tight turns), the tangent vector would flip abruptly, causing the icons to interpret "up" as "down," rotating 180º suddenly. 

To fix this and give you more artistic control, I implemented a "Smart Rotation" system with three modes: 

1. Fixed Mode (Full Correction): Now you have a checkbox Align to Curve. If you deactivate it, the items completely ignore the curve's wild rotation and stay always vertical (or at the angle you choose). This solves the vertical flipping of items at the ends and normalizes the angle of all items on the curve. 
2. Fan Mode (Accumulative): With the Fan Angle slider and the Accumulative option activated, you can make the items fan out like a deck of cards (e.g., -10º, -5º, 0º, 5º, 10º). I got the idea thinking about how to keep both characteristics haha.
3. Mode "Wings" (Equal): If you disable Accumulative, the angle is applied equally to the sides but mirrored (e.g., all on the left face -5° and those on the right 5°). I think it can help correct the visual perspective in concave or convex curves without distorting the center, and it originated from the cumulative solution haha.
   

I hope this has solved your problems and allows you to use the plugin more comfortably and with greater artistic freedom! I look forward to your comments and thank you very much.

Extended explanation Devlog.