In Minecraft versions 1.9 to 1.19, trapdoors could be climbed when placed in line with ladders. In version 1.20, this behavior has been removed or broken. There are existing bug reports concerning trapdoors being climbable, and it's possible this change was made in response to those reports.
Motivation:
When climbing a ladder up to a floor with a trapdoor and opening it, if there's another ladder above the trapdoor, it can be challenging to climb through or jump to the next floor, as the player might be blocked by that ladder. As a result, the ladder often needs to be removed to access the floor and then replaced to climb further. This workaround can be cumbersome. To avoid this issue, players might resort to replacing the trapdoor with a ladder that remains open. This behavior suggests that players value the trapdoor's former functionality and would benefit from its return.
Suggested Solution:
To improve user experience, a visual indication could be introduced to signal whether a trapdoor allows climbing based on its position relative to a ladder. When a trapdoor is closed, players should see the ladder through it if it's aligned with one, indicating that climbing is possible when opened. If the trapdoor is placed at the top of a ladder, it should visually connect with the ladder below; if placed at the bottom, it should connect with the ladder above.
To avoid confusion when trapdoors are placed alongside other climbable items like vines, the trapdoor should always allow climbing if it's connected to such items.
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Comments 10

Thank you for your report!
However, this issue has been temporarily closed as Awaiting Response.
Is this still an issue in the latest version? If yes, could you please add it to the affected versions (or mention it if you are not the reporter)?
This ticket will automatically reopen when you reply.
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Can confirm the issue is not fixed in 1.21.51. I have attached a test world.
[media]Steps to Reproduce - Using test world
Follow all the signs.
Try climbing the ladder.
If you can't get past the open trapdoor, the bug is not fixed.
Edit:Â This comment was updated to prevent comment clutter.
Confirmed in Android, Relates to MCPE-30863 (This was resolved as Invalid for Parity issue)
The issue still pretty much persist in 1.21.51 Hotfix However in some occasions you can actually climb past open trapdoors but most of the time you wouldn't be able to