Infobox nested panels bug

Wikitext input
Section 1.1 Section 1.2

Rendered output
Section 1 Section 1.1 Section 1.2

Wikitext input
Section 1.1 Section 1.2 Section 2 Section 2.1 Section 2.2

Rendered output
Section 1 Section 1.1 Section 1.2 Section 2 Section 2.1 Section 2.2