Not all bedrock is replaced with deepslate when updating some worlds to 1.18

I updated my old world since 0.9.0 to 1.18 and got to 0 level to look on new caves generation
I found out what most of bedrock blocks on 0-5 levels haven't replaced with deepslate and stayed as they was.

Steps to Reproduce:

1. Download and open the attached world
2. Dig down to Y=0

Observed Results:
Some of the bedrock hasn't been replaced with deepslate.

Expected Results:
All bedrock should be replaced with deepslate.