No, this is normal. If you're using the experimental version of Minecraft, you're seeing the soon-to-be-added ruined portals. These generate in the nether and the overworld. Congrats on finding one!
this exact thing is happening to me as well (1.14.60, windows 10 edition). i already wrote a report about it. i see that this issue is resolved and i would love to know how! i really want to play in my world.
No, this is normal. If you're using the experimental version of Minecraft, you're seeing the soon-to-be-added ruined portals. These generate in the nether and the overworld. Congrats on finding one!