Glow Squid are violating spawning rules per the official wiki (wiki may be incorrect but it is the only reference I have at this time).

Per the Wiki

Groups of 2-4 glow squid spawn underwater below sea level (y = 63) in total darkness and where there is a block with base_stone_overworld tag (i.e. stone, deepslate, andesite, diorite, granite or tuff) less than 5 blocks below the spawning space.

Emphasis on 'below'. I built a stone platform in deep ocean at about Y=55 then constructed a roof of the same dimensions in air at y=65. The ocean floor is at least twenty blocks below the lower platform at all points so there is no chance of anything '5 blocks below'. Some Glow Squid were spawning above the platform but many were spawning beneath it as well.

What I expected: All glow squid would spawn between the stone platform and the roof.
What I observed: Many Glow Squid spawning beneath the platform

How to reproduce:

1. Construct a platform and roof as described above. Length and width shouldn't matter but mine was about 20 blocks by 10 blocks.
2. Observe