when I use a resource pack, it is not able to show parts hidden by other blocks
Without texture pack:

Without texture pack; (Faithful 32x - 1.20.1)

With texture pack + texture connect: (Stay True_1.20)

For the record, which resource pack are you using? Knowing this will make it easier to reproduce the issue

Here are the 2 texture tester packs

Faithful doesn't have a connected texture but Stay True has a connected texture

Are you also using OptiFine in tandem with these, or any other mods?

I use iris, I am under fabric

the problem is linked to the continuity mods but it is this mod that manages the texture packs