You can attach lantern to all solid blocks / slabs / straight oriented stairs from the bottom side.
However, you can't do that with many others blocks with flat botton texture. For instance - enchanting tables, campfires or leaves.
This bug greatly affects the decorating process. For example, in JE, a lantern attached from botton side to an extinguished campfire is a classic chandelier.
In the Java edition, this bug is not present (lanterns can be hung on almost anything), so it will be nice if you add some parity between editions in this regard.
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Thank you for your report!
We're tracking this issue in MCPE-51416, so this ticket is being resolved and linked as a duplicate.
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