Steps to reproduce the issue

1. Create a form with a Subform inside a Subform inside another Subform (3 levels deep).

2. Use the showon attribute to conditionally display a subform field, for example:

   showon="type:checkbox,radio,list"

3. Load the form and try adding a new subform entry at the third level using the "+" button.

Expected result

The subform at the third level should allow adding new entries without breaking or any unexpected behavior.

Actual result

While the third-level subform initially works, clicking the "+" button to add another nested item results in broken functionality or UI glitches. The new subform fields may not render correctly.

System information (as much as possible)

• Joomla version: [Add your Joomla version, e.g. 4.4.2]
• PHP version: [e.g. 8.1.x]
• Browser: [e.g. Chrome 125]
• Template Framework: [If applicable]
• Extension: Core subform and showon feature

Additional comments

This issue appears to be related to Joomla core, as we are not using any custom scripts—just core subform and showon behavior. Here's a video demonstrating the issue:
http://sc.com.ly/show/cccc2282-9697-48ee-ac8e-3b9af5c92ebe

Please let us know if this is a known limitation or if there's a recommended workaround.

Thanks!