When any entity lands on a moving block of any type moved in any direction (even down), it show the "update block" landing particles instead of the blocks landing particles. I do not know if this is specifically the update block's texture, but its my best guess to what the particles are.
[media]
Thank you for your report!
We're actually already tracking this issue at MCPE-63428, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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