After the fix for MCPE-40407, scaffolding can now be placed on all the non-solid blocks that are supposed to support it. However, if the scaffolding falls on most of those blocks, it breaks.

The blocks that break falling scaffolding (but shouldn't) are:

• Top Slab
• Upside-down Stairs
• Hopper
• Grass Path
• Stained Glass Block
• Cauldron
• Composter

Steps to reproduce:

1. Place 3 Stone blocks in a row vertically.
2. Place any of the above blocks in front of the bottom Stone block.
3. Place a Scaffolding block on the side of the topmost Stone block, above the chosen block.

Alternatively, you can use the attached world to reproduce the issue.

Observed results:
The scaffolding falls, breaking when it hits the chosen block.

Expected results:
The scaffolding becomes a block and can be used as the base for a tower of scaffolding.

Impact:
Many Bedrock players make their interior floors out of top slabs to take advantage of Bedrock's unique ability to light a room with underfloor lighting. But such a floor confers the disadvantage that it becomes more difficult to use scaffolding to build the rest of the room. Once you've built a vertical support tower and extended it sideways to the limit of its capacity, you're supposed to be able to drop scaffolding blocks off the end to build another support tower and extend farther. But this forces you to climb down, go to where you want the new tower, and build it up from the ground instead.