With the full release of 1.17 Java Edition on June 8, 2021 the following change was made:
A Shulker hitting a Shulker with a Shulker Bullet can make a new Shulker
This feature has been absent from the Bedrock edition since its introduction & has remained a Java exclusive feature.
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We're tracking this issue in MCPE-104826, so this ticket is being resolved and linked as a duplicate.
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