Smooth Quartz does not have a smooth texture, it has the texture has normal quartz block. Also, Red Sandstone Stairs have a sideways texture which make the lin appear on the sides and the bottom. Both of these are really annoying because I really want to build with them.
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Thank you for your report!
We're already tracking this issue at MCPE-42276, so I will resolve and link this ticket as a duplicate.
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