This vanilla parity issue is related to
MCPE-155213. The fix for that issue was to raise the Y height in the 'sculk_patch_feature.json' file to allow sculk patches to generate up to Y 256, which was successfully deployed in 188.8.131.52 / 184.108.40.206.
However, there is a related file named 'sculk_vein_feature.json' which controls generation of the isolated decorative sculk veins in the Deep Dark. This file still has its Y range limited to 20 instead of 256, causing the decorative sculk veins to stop generating at that height. (It also has its low-end value set to -64 instead of -63, which seems odd since the world bottom does not go below Y -63. But perhaps there is a technical reason for allowing generation to Y -64 with sculk veins?)
While this is not a big deal, the fix is fairly quick and it would be nice to have the decorative sculk veins in sync with their sculk patch counterparts for all the permanent worlds generated by the official 1.19 Wild Update release. Java edition already generates both the sculk patches and decorative sculk veins up to Y 256, which is why this issue is labeled as a parity issue.
Attached are screenshots highlighting the differences between Java and Bedrock. The seed and coordinates are displayed in the screenshots.
bedrockY14.jpg - proper sculk veins below Y 20.
javaY64.jpg - proper sculk veins above Y 20.
bedrockY64.jpg - missing sculk veins above Y 20.