504 error while updating group

Describe the bug
When I try to add a user to a group via the API I get the 504 error

To Reproduce
Steps to reproduce the behavior:

curl -X 'PATCH'
'https://vpn2/api/v2/user/group'
-H 'accept: application/json'
-H 'x-api-key: '
-H 'Content-Type: application/json'
-d '{
"id": 3,
"name": "Test",
"scope": "local",
"description": "",
"member": [
"testgebruiker1"
],
"priv": null
}'

Expected behavior
That the user is added to the group

Screenshots or Response

<title>50x Error</title> <script type="text/javascript"> // </script> <script src="/vendor/jquery/jquery-3.7.1.min.js"></script> <script src="/vendor/bootstrap/js/bootstrap.min.js"></script> <script src="/vendor/bootstrap/js/bootstrap.min.js"></script> <script> $(function(){ $("#logodiv").load("logo.svg"); }); </script>

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						The web server encountered an error processing this request.<br/>
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						Check the <a href="/crash_reporter.php">Crash Reporter</a> for details.
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						<h4>50x Error</h4>
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pfSense Version & Package Version:

pfSense Version: 25.07.1
Package Version: 2.6.3

Affected Endpoints:

URL: /api/v2/user/group