End portals (as in the actual end portal blocks, not end portal frame blocks) do NOT obstruct beds. This means that you can place a bed under an end portal, sleep in it, and your spawnpoint will be set in the end portal. This can lead to survival players being permanently trapped in The End, as they will just end up teleporting back when they kill themselves. It is possible to get out in multiplayer if another player breaks the bed, but this is not a solution for singleplayer. Additionally, I don't think it makes sense that portals of any type are not considered obstructions to beds, but of course, this is up to the developers to decide.
Steps to reproduce
Build/find an end portal in the overworld and activate it.
Place a bed directly underneath the portal, so that both ends of the bed are under end portal blocks and the player will spawn in the end portal.
Set the time to night. (
/time set night
)Enter the bed.
When the player wakes up, they will be instantly teleported to The End.
Switch to survival mode if you are not already, and kill yourself.
Notice that when you respawn, you end up teleporting to The End instantly, trapping you there permanently until the bed is broken or your spawnpoint is otherwise changed.
Other notes
If cheats are enabled, you can use /spawnpoint
to change your spawnpoint to somewhere other than the end portal in the overworld, allowing you to escape. This is not an option for survival worlds with cheats disabled, however.
Bonus: After setting up this bug and effectively trapping yourself in The End, use /setblock ~ ~-1 ~ portal
to place a nether portal block in The End, and try entering it. You'll end up travelling to the overworld, but then get teleported back to The End... but the sky will change from the normal void sky to the Overworld sky. Entering the nether portal again will change the sky back to normal.
Linked issues
is duplicated by
Comments

This still happens in 1.2.8 - where if there's an end portal where you spawn, you respawn in the end with the sky looking like that of the overworld.

This can happen with the world spawn point too.

I tested this, it no longer works for beds(can't place them in the same place), but it can be reproduced if you make an end portal on the world spawn point or /spawnpoint on an end portal.
in v1.2.9

Made new report:
MCPE-30013
This bug has been reported to our internal bug tracker for further testing and a fix. It is scheduled to be fixed in one of the future updates (no specific date can be provided).