Posted by dellus on Jan 07, 2021; 5:56pm
URL: https://forum.librecad.org/Fillet-and-Bevel-on-polylines-problem-tp5720031p5720032.html

I have just tested it and have to confirm it. I don't know the reason, but there are many imperfections with LibreCAD, we have to live with it.
When drawing a polyline you want to be closed, when you have done the last point before closing, then press the "Close" button in the Tool Options bar above the drawing area. It will close automatically then, and the difference is, the start/end point responds to fillet then! Just found out.