Unlike the Java edition, the campfires can be seen through trapdoors if you are a few blocks far along with it's smoke cutting out and no longer being visible after walking about 40 blocks away from it kind of ruining the vibe of a chimney build for example. Pretty sure this is a bug regarding the smoke's radius range, hopefully it becomes fixed in the newest updates/hotfixes.
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We're tracking this issue in MCPE-141737 and MCPE-42512, so this ticket is being resolved and linked as a duplicate.
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