In creative mode, the nether portal does not break completely when the portal is not in the default size.

In creative mode, when I build a Nether portal with the Default size (2x3), when I break the portal itself (not the obsidian below), the portal breaks completely. But whent I build a nether portal with a size other than the default, when I break the portal itself, only the block I target breaks, not the complete portal. https://www.youtube.com/watch?v=SS19frUtGX0