Placing an end portal with each of the frame blocks rotated 90 degrees will spawn the end portal blocks in the wrong place.

Expected behaviour: Spawn no portal (intended), or spawn a portal in the middle of the frame

Actual behaviour: Spawned portal north of the frame if the frame blocks were rotated clockwise 90 degrees, or spawned portal west of the frame if the frame blocks were rotated counterclockwise 90 degrees.

This portal appears to exist in quantum form, where activating a frame block next to where-the-wrong-portal-would-be causes that portal to spawn (see: 2019-12-05_20.10.27.png → 2019-12-05_20.10.28.png).