I am using the svg widget below from this answered question
Capture Signature using HTML5 and iPad
to create a capturable signature. The code as is works but when I put content above it such as text in a <p> tag it’s stops working, which is problematic as I need it at the bottom of a document. Does anyone know why it stops working and how to make it work no matter where it is positioned in the html page?

//init
let r = document.getElementById('r'),
  p = document.getElementById('p'),
  signaturePath = '',
  isDown = false,
  svg = document.getElementById('sig_panel'),
  b_show = document.getElementById('show'),
  b_clear = document.getElementById('clear'),
  pathdata = document.getElementById('pathdata');

//drawing functions
function isTouchEvent(e) {
  return e.type.match(/^touch/);
}

function getCoords(e) {
  if (isTouchEvent(e)) {
    return e.targetTouches[0].clientX + ',' + e.targetTouches[0].clientY;
  }
  return e.clientX + ',' + e.clientY;
}

function down(e) {
  signaturePath += 'M' + getCoords(e) + ' ';
  p.setAttribute('d', signaturePath);
  isDown = true;

  if (isTouchEvent(e)) e.preventDefault();
}

function move(e) {
  if (isDown) {
    signaturePath += 'L' + getCoords(e) + ' ';
    p.setAttribute('d', signaturePath);
  }

  if (isTouchEvent(e)) e.preventDefault();
}

function up(e) {
  isDown = false;

  if (isTouchEvent(e)) e.preventDefault();
}

//input handlers
r.addEventListener('touchstart', down, false);
r.addEventListener('touchmove', move, false);
r.addEventListener('touchend', up, false);
r.addEventListener('mousedown', down, false);
r.addEventListener('mousemove', move, false);
r.addEventListener('mouseup', up, false);
r.addEventListener('mouseout', up, false);

//helper functions
function clearSignature() {
  pathdata.textContent = '';
  signaturePath = '';
  p.setAttribute('d', '');
}

function getSignature() {
  pathdata.textContent = signaturePath;
  return signaturePath;
}

//button handlers
b_show.addEventListener('click', getSignature);
b_clear.addEventListener('click', clearSignature);
svg {
  margin: .5em;
  border: 1px solid gray;
  border-radius: .5em;
}

.flex {
  display: flex;
}

button {
  margin: .5em;
}

#pathdata {
  font-family: monospace;
  background: #ddd;
  padding: 1em;
  margin: 1em .5em;
}
<svg id="sig_panel" xmlns="http://www.w3.org/2000/svg" width="300" height="100" viewBox="0 0 300 100">
  <rect id="r" width="300" height="100" fill="#ffa"/>
  <line x1="0" y1="80" x2="300" y2="80" stroke="#666" stroke-width="1" stroke-dasharray="3" shape-rendering="crispEdges" pointer-events="none"/>
  <path id="p" stroke="navy" stroke-width="2" fill="none" pointer-events="none"/>
</svg>
<div class="flex">
  <button id="show">Show signaure path data</button>
  <button id="clear">Clear signature</button>
</div>
<div id="pathdata"></div>