Some jQuery listeners in core js files attached twice when EU Cookie Compliance is enabled

[argiepiano]

Description of the bug

I'm unsure if this is a core issue, or a problem with EU Cookie Compliance, or both. This was originally reported in the forum, and there is a new issue in the EU Cookie Compliance module. I'm posting it here as well in case this is a problem with core.

There are at least two JS files with event listeners attached to more/less toggle links which are being attached twice: modules.js and status.js. This causes the listener to fire twice, effectively canceling the action (open/close of toggle in rapid succession - this can only be detected with a JS breakpoint, as it's not visually possible to detect).

Steps To Reproduce

1. Install EU Cookie Compliance
2. Visit admin/modules/list and admin/reports/status
3. Click the more/less toggle -nothing seems to happen (no opening or closing)

To verify this is called twice:

1. Deselect "Aggregate Javascript files" in admin/config/development/performance . Navigate to admin/modules/list
2. In Chrome's dev tools -> Sources, find modules.js and insert a breakpoint in line 20
3. Click the more/less toggle and watch the callback function being called twice

Additional information

Some other js files like contextual.js seem unaffected. One thing I noticed is that contextual.js wraps all the listener attachments with a jQuery.once(), which effectively avoids the double-attachment of listeners. So, I'm wondering if jQuery.once() should also be used in modules.js and status.js to wrap these attachers?

• Backdrop CMS version: 1.22.0
• Chrome v. 103