More NaN's showing up in output glyphs

[ctrlcctrlv]

[fred@🍇葡萄🍇build]$ MFEKstroke CWS -i BUILD.ufo/glyphs/m.high.glif -w 40 -o /tmp/m.high.glif
[fred@🍇葡萄🍇build]$ vim !$
vim /tmp/m.high.glif
[fred@🍇葡萄🍇build]$ rg -c NaN !$
rg -c NaN /tmp/m.high.glif
4
[fred@🍇葡萄🍇build]$

m.high.glif

<?xml version="1.0" encoding="UTF-8"?>
<glyph name="m.high" format="2">
  <advance width="676"/>
  <outline>
    <contour>
      <point x="0" y="171" type="move" smooth="yes"/>
      <point x="113" y="171"/>
      <point x="117" y="261"/>
      <point x="187" y="261" type="curve" smooth="yes"/>
      <point x="205" y="261"/>
      <point x="213" y="250"/>
      <point x="213" y="232" type="curve" smooth="yes"/>
      <point x="213" y="177.961"/>
      <point x="96.1097" y="17.4424"/>
      <point x="79" y="-7" type="curve"/>
      <point x="114.227" y="43.7249"/>
      <point x="244.829" y="260"/>
      <point x="369" y="260" type="curve" smooth="yes"/>
      <point x="389" y="260"/>
      <point x="403" y="251"/>
      <point x="403" y="231" type="curve" smooth="yes"/>
      <point x="403" y="184.074"/>
      <point x="291.759" y="19.1719"/>
      <point x="274" y="-9" type="curve"/>
      <point x="274" y="-10" type="line" smooth="yes"/>
      <point x="274" y="-10" type="line"/>
      <point x="274.227" y="-10"/>
      <point x="434.767" y="263"/>
      <point x="578" y="263" type="curve" smooth="yes"/>
      <point x="594" y="263"/>
      <point x="599" y="253"/>
      <point x="599" y="244" type="curve" smooth="yes"/>
      <point x="599" y="183.871"/>
      <point x="496" y="108.996"/>
      <point x="496" y="29" type="curve" smooth="yes"/>
      <point x="496" y="10"/>
      <point x="504" y="0"/>
      <point x="524" y="-0" type="curve" smooth="yes"/>
      <point x="539" y="0"/>
      <point x="602" y="25"/>
      <point x="676" y="77" type="curve" smooth="yes"/>
    </contour>
  </outline>
</glyph>

[ctrlcctrlv]

Solved by MFEK/math.rlib@a85434f (or the commit immediately prior, I am not sure)