Basically i'm being able to destroy nether portal frames without the portal being deactivated. The only thing that happens is that that spot stops working. Now i have a nether portal frame flying, like shown in last screenshots. And yes, all i did was destroying the obsidian after the screenshots. I've even entered the nether and reloaded the world, still the same. If two nether portals are created one next to each other, the nether frames become invisible. In the last screenshot i just combined both glitches and made an invisible nether portal flying in the air without any obsidian around.