My friends and I have been playing on survival in a realm, and I recently found an end portal. We decided to fight the dragon and set off to the portal. However, one friend built dirt and roses beneath the portal as a joke.

I've read that activating the portal is supposed to destroy any blocks that would be in its way, and attempted to add the last eye to a frame. The portal failed to activate even after removing the roses, dirt, etc. We have been unable to fix the portal and do not want to disable achievements by going into creative. Of course the eyes cannot be removed, so it seems my portal is permanently broken.

What worked:
• Downloading the world and replacing a frame in creative. The portal activates once a frame is replaced and filled without obstacles.

Reproducing the problem:
• I tried adding the roses again before activating the portal, and it again failed in Creative.
• Placing dirt inside also breaks the portal, as it apparently cannot activate with obstacles.

The attached screenshot is my view of the broken portal (accessed via Pocket Edition).