ezdxf drawing add-on raises 'More than 1 vertex required' on a 1-vertex LEADER and the whole DXF fails to render

Delete degenerate leaders (they draw nothing anyway) from modelspace and every block before rendering:

import sys
def drop_degenerate_leaders(doc):
    n = 0
    for layout in [doc.modelspace(), *doc.blocks]:
        for e in list(layout.query("LEADER")):
            try:
                ok = len(e.vertices) >= 2
            except Exception:
                ok = False
            if not ok:
                layout.delete_entity(e); n += 1
    if n:
        print(f"dropped {n} degenerate LEADER(s)", file=sys.stderr)

doc = ezdxf.readfile(path)
drop_degenerate_leaders(doc)

An alternative used in another tool: wrap per-entity drawing in try/except and skip failures.