I was shooting fireworks through an end portal with my multishot crossbow. Some just go through the portal and explode on the ground beneath it.

I was expecting the fireworks to go to the end through the portal
It happened that they just passed through it without leaving the overworld
To reproduce: take a crossbow and shoot some fireworks through an end portal. Especially those that do explode, as it is more apparent when they don't leave the starting dimension.