Whenever some bastion remnants like the hoglin stable generate out in a lava ocean, the lower part of the structure floats over the lava. It has been this way since 1.16 was released, I believe this is a bug since it looks odd, and it would make much more sense if the structure generated one block lower.
Thank you for your report!
We're tracking this issue in MC-236269, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support (Technical Issues) – 📧 Microsoft Support (Account Issues)
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki