If you place a closed trapdoor, (or carpet, not sure if it is intended) on top of a slime block the effects of slime, eg: slower movement, bouncyness, and fall damage negation remain, regardless if the block above contains a closed trapdoor.
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Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-1127, which has been marked as Works as Intended - this is an intentional game feature. If you have a different opinion, please visit the Feedback website.
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