It seems that stairs are the same as glass that cannot shade zombies against the sunlight to prevent zombies from burning. Why I regard it as a bug is that zombies will burn under a stair, which amounts to three quarters of a block, but not burn under a slab, which amounts to a half of block. It is unreasonable that stairs contain more substances but have less ability to stop light. I hope this bug can be fixed as soon as posible.
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Thank you for your report!
We're actually already tracking this issue at MCPE-363, so I will resolve and link this ticket as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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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Thank you for your report!
We're actually already tracking this issue at MCPE-363, so I will resolve and link this ticket as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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:
π Bug Tracker Guidelines β π¬ Community Support β π§ Mojang Support
π Project Summary β βοΈ Feedback and Suggestions β π Game Wiki