On occasion, attempting to use an ender pearl to teleport through an End portal will simply result in the ender pearl passing through the portal as if it were not there, instead teleporting the player when it impacts the ground below the portal. This is particularly noticeable when throwing the pearl directly downwards toward the portal. It also seems to be more likely when using an angle that would result in the ender pearl impacting the side of an end portal frame block.

Steps to reproduce:

1. Activate an End portal.
2. Throw an ender pearl into the portal.
3. Observe that the ender pearl may simply pass through the portal and attempt to teleport the player to the ground below the portal, instead of taking the player directly to the End dimension.

This is more easily observed in creative mode, where this can be tested while flying and will usually cause the player to teleport just above the portal when the ender pearl attempt fails. I have had this occur many times in a row during testing when using an angle that involves throwing the ender pearl directly downwards at the portal. It appears to occur more commonly when at a distance of approximately 10 or more blocks from the portal.