Sometimes lava generates underwater and doesn't turn into obsidian

Steps to reproduce:

Seed:892344456031888

/tp 70 -50 231

Observed result:

Lava generates underwater and doesn't turn into obsidian.

Expected result:

When lava generates underwater, it always turns into obsidian.

Notes:

This happens since 1.16 or earlier.

Similar to MCPE-140185.