If you set up scaffolding in certain ways near non-full blocks as shown in the screenshot with bells, then try to walk on the scaffolding block from the bells, you will stutter in place, a little like client/server desync-related ghost blocks, before eventually falling off.
Thank you for your report!
However, this issue has been closed as Cannot Reproduce.
I am unable to reproduce this, the feature behaves as expected in 1.16 Release Candidate 1.
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