Redstone dust updating has changed in 1.20, and redstone dust is also redirected by dust on an open trapdoor.
reproduce:
part 1: build the contraption in attachment in 1.19.4 and 1.20, placing the dust on the trapdoor last. You won't be able to place the redstone dust on the trapdoor in 1.20.
Part 2: Build the redstone line in 1.19.4 and 1.20. the redstone goes straight in 1.19.4 when you open the trapdoor while in 1.20 the redstone stays curved.
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Thank you for your report!
We're tracking this issue in MC-157300 and MC-3703, so this ticket is being resolved and linked as a duplicate.
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Does not in fact duplicate either of them. This involves redstone being different between 1.19.4 and 1.20. It's a new (likely unintended) change.

Can this be reopened? As stated previously, this is not a duplicate.
Duplicate of MC-3703 and MC-157300.