While the game is transporting you to the Nether, you can take damage (and die) from hostile mobs while it is still loading. Load times are significant on the Nintendo Switch version.
Scenario:
Enter the Nether portal from the Overworld.
While the loading screen is still up, you hear a Ghast, it fires at you, and you die before the loading screen ever finishes.
Try to re-enter the Nether to collect everything you just lost and apparently the Ghast broke a block that spewed lava over the portal and all you hear is you taking damage and dying from the lava before the loading screen ever finishes.
Now you are unable to enter the Nether and you were never given an opportunity to begin with due to taking damage and dying before the Nether dimension ever loaded for gameplay.
This is a disheartening bug. Significant load times can be tolerated; however, the issue here is, you are able to take damage (and die) before the gameplay is even loaded.
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Thank you for your report!
We're tracking this issue in MCPE-42310, so this ticket is being resolved and linked as a duplicate.
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