Original bug has been listed as resolved. Please reopen kriginal bug report.

Patch notes 'Fixed some worlds not correctly replacing Bedrock blocks with Deepstone blocks after upgrading to 1.18 (MCPE-149251)'.

In my world all chunks that existed prior to 1.18 are still showing bedrock at the old Y level (6 and below).

Bedrock has been created down to Y -64, but not replaced.
When loading up world yesterday I downloaded the Hotfix and my world still has solid bedrock from Y0 to Y-64.

Expected results.
Patch / Hotfix would have replaced all bedrock in chunks generated prior to 1.18 with Deepslate .

Experienced results.
Bedrock has not been replaced with Deepslate.