I've encountered an issue I've been able to freely replicate. My game freezes at "Building Terrain" when I,
Go to the Nether
Place a powered minecart rail with a redstone torch below the block (Active).
Leave the Nether through the same portal.
After hard restarting the game, I appear back in overworld in the general area that the portal is and can repeat the above process. When I remove all of the powered rails I placed in the Nether, this issue doesn't happen. The person I'm playing with doesn't have this issue, they can freely use the portal whereas I get stuck.
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Thank you for your report!
We're actually already tracking this issue at MCPE-44815, so I resolved and linked this ticket 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.
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