It is because min attribute in the nested subfrom seems buggy. Without min="1" it works fine.
About radio switch, there already an issue #40160

Thanks a lot! I ll remove it then <3
Removing min attribute also fixed the show on functionallity.

If i find something it could help more i ll attach it here!

Note: this also happen when nested subform have default value.

When using a inside another subform (i.e. nested subforms), and setting min="1" on the nested subform, Joomla renders one default entry during form load. However, at that point, the outer subform's index is still unknown (e.g. sectionsX), resulting in invalid name attributes like:

name="jform[sections][sectionsX][subsections][subsections0][id]"

These placeholders are never replaced with actual indexes, so the form breaks on submit or validation. This only happens on initial load — dynamically added rows via the "+" button work correctly because the correct parent index is known by then.

To support min="1" in nested subforms without breaking field names, you can add the following code after this.fixUniqueAttributes(row, count); inside the addRow() method:

// Replace placeholder index 'X' in name attributes for nested subforms.
const nameAttr = this.name || '';
const match = nameAttr.match(/[?(\w+)]?$/);
if (match) {
const groupName = match[1];
const pattern = new RegExp((\\[${groupName})X(\\]), 'g');

row.querySelectorAll('[name]').forEach(el => {
el.name = el.name.replace(pattern, $1${count}$2);
});
}

This replaces placeholders like [sectionX] with [section0], [section1], etc., based on the current subform index.
The replacement is scoped to the correct group name by dynamically extracting it from this.name — although I’m still wondering whether this name is always accurate, since the generated field names often use a plural form (e.g. sections) instead of the singular field name (section).