The 1.16.200 update fixed a bug where End Portal blocks were not removed after an End Portal Frame block was destroyed, this change created a small issue. If an End Portal Frame block is in the corner of the portal, it is considered part of it.

One consequence of this is that breaking the corner End Portal Frame block causes the portal to deactivate.

The other consequence of this is that breaking an End Portal Frame block in the original portal can make it not deactivate.

The final consequence of this, that I know of, is that lighting the corner portal causes the portal to re-light.

Steps to Reproduce

Create, and light an end portal.

Place an End Portal Frame block in one of the corners.

Bug #1 - Break the corner End Portal Frame block.

Bug #2 - Facing the corner End Portal Frame block, break the End Portal Frame to its left.

Bug #3 - Break End Portal block(s), then light the corner End Portal Frame block.

Notes

This could be fixed by returning to parity with java edition by allowing players to break the End Portal Frame block without the End Portal blocks being removed.