Eli: keep trying to log in over and over. Each log-in causes a little game time to pass, so after about 20 or so failures, the firework will despawn, and you will be able to get in.
God help you if there is a dispenser full of fireworks on a redstone loop 😛
Griefers apparently can use this as a denial-of-service attack 😞
I know this is by design, but it is still pretty annoying that your overworld will get full of one-way portals. I am in the habit of labelling one-way portals with signs, but it would be really awesome if the game could detect whether a portal in the overworld is a "Master" portal for that1024x1024 area, or if it is a one way portal, and give some visual indication of the difference, for example, master portals could be purple, and one-way portals could be red, or maybe master portal animation could swirl clockwise and one-way portal animation could swirl counter-clockwise
I am going to guess that "Minor" is the default priority, and nobody with permissions to edit the priority has noticed this bug yet.