Thank you for your assistance Paul, I had already looked in the head to make sure things looked correct, and to my eyes they do.
My code is below, I just created a new Wappler 4.1.3 nodejs project with Bootstrap 5
The code below is as Wappler added the accordion cards with paragraph text shortened for readability
<!-- Wappler include head-page="layouts/main" fontawesome_5="cdn" bootstrap5="local" is="dmx-app" id="index" appConnect="local" components="{dmxBootstrap5Collapse:{}}" -->
<div class="accordion" id="accordion1">
<div class="card">
<div class="card-header" id="accordion1_headingOne">
<h5 class="mb-0">
<button id="accordion1_collapseOne_Btn" class="btn btn-link" type="button" data-bs-toggle="collapse" data-bs-target="#accordion1_collapseOne" aria-expanded="true" aria-controls="collapseOne">
Collapsible Group Item #1
</button>
</h5>
</div>
<div id="accordion1_collapseOne" class="collapse" is="dmx-bs5-collapse" show="true" aria-labelledby="accordion1_headingOne" data-bs-parent="#accordion1">
<div class="card-body">
Anim pariatur cliche reprehenderit, ....
</div>
</div>
</div>
<div class="card">
<div class="card-header" id="accordion1_headingTwo">
<h5 class="mb-0">
<button id="accordion1_collapseTwo_Btn" class="btn btn-link collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#accordion1_collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
Collapsible Group Item #2
</button>
</h5>
</div>
<div id="accordion1_collapseTwo" class="collapse" is="dmx-bs5-collapse" aria-labelledby="accordion1_headingTwo" data-bs-parent="#accordion1">
<div class="card-body">
Anim pariatur cliche reprehenderit, ....
</div>
</div>
</div>
<div class="card">
<div class="card-header" id="accordion1_headingThree">
<h5 class="mb-0">
<button id="accordion1_collapseThree_Btn" class="btn btn-link collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#accordion1_collapseThree" aria-expanded="false" aria-controls="collapseThree">
Collapsible Group Item #3
</button>
</h5>
</div>
<div id="accordion1_collapseThree" class="collapse" is="dmx-bs5-collapse" aria-labelledby="accordion1_headingThree" data-bs-parent="#accordion1">
<div class="card-body">
Anim pariatur cliche reprehenderit, ....
</div>
</div>
</div>
</div>
<meta name="ac:route" content="/">
Below is my head section
<html>
<head>
<base href="/">
<script src="dmxAppConnect/dmxAppConnect.js"></script>
<meta charset="UTF-8">
<title>Untitled Document</title>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.14.0/css/all.css" integrity="sha384-HzLeBuhoNPvSl5KYnjx0BT+WB0QEEqLprO+NBkkk5gbc67FTaL7XIGa2w1L0Xbgc" crossorigin="anonymous" />
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="bootstrap/5/css/bootstrap.min.css" />
<link rel="stylesheet" href="css/style.css" />
<script src="dmxAppConnect/dmxRouting/dmxRouting.js" defer=""></script>
<script src="dmxAppConnect/dmxBootstrap5Collapse/dmxBootstrap5Collapse.js" defer=""></script>
</head>
<body is="dmx-app" id="main">
<div is="dmx-view" id="content">
<%- await include(content, locals); %>
</div>
<script src="bootstrap/5/js/bootstrap.bundle.min.js"></script>
</body>
</html>
So to confirm, the accordion section that is clicked does expand when clicked, and retract when clicked again. meaning each click toggles the specific accordion section, BUT leaves all other already open accordion sections open.
This behaviour is not default Bootstrap 5 behaviour and is controlled by the presence or not of the following in the accordion collapse section
data-bs-parent="#accordion1"
So my understanding is that with <<< data-bs-parent="#accordion1" >>> PRESENT any accordion button clicked should open that accordion and CLOSE any already open ones.
In reverse with <<< data-bs-parent="#accordion1" >>> OMITTED any accordion button clicked should open that accordion and LEAVE any already open ones alone.
In Wappler generated code <<< data-bs-parent="#accordion1" >>> is PRESENT, however it behaves as though it is omitted (have tried ommitting it to see if Wappler is working in reverse, but no such luck)
Now when I paste Bootstrap 5 code for the accordion default behaviour from their website into Wappler it works as I expect.
One key difference between Wappler generated Accordion code and Bootstrap 5 code from their website is that Wappler adds
is="dmx-bs5-collapse"
When I remove the above it works fine, and behaves as I expect.
What does <<<is=“dmx-bs5-collapse”>>> actually do, and why is it needed (am certain their is a good reason for it, but that’s where I am out of my depth)?
It is looking like a Wappler bug from what I am seeing, but am surprised this is not picked up already, which makes me question my understanding?
Any thoughts Paul, or anyone?