So, I found a bug with Nether-Portals.
If you build a portal and the destination in the Nether would be inside a "mountain" with no space from top to bottom of the Nether, the portal generates at a near open space.
Now to the actual Bug.
If you leave the Nether to this generated portal you generate a new one in the Overworld at matching coordinates (wich is nothing new) BUT the wold does't load propperly (Mobs stuck where they are, you cant pickup Items, only 3x3 Chunks are "loaded") and you need to exit and open this world again. after that rejoin everything is normal.
Only mod used: Optifine_HD_G9_pre17
Linked issues
duplicates 1
Comments 2
Thank you for your report!
We're tracking this issue in MC-227996, 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
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
Duplicate of MC-227996. This issue is caused by Optifine. Disable this modification to resolve the issue.