I had a problem with this mod and found out half of the problem was OptiFine. So I tested with both, just Immersive Engineering, and then OptiFine. I do have other mods, but you'll understand why I bother removing those (even though it's possible they can be causing the problem some how)

My Testing Results:

1. When Immersive Engineering AND OptiFine are both installed:

• There is a problem where I can see certain parts of caves when I look through the surface of water.
• Also causes an "OpenGL Error: 1282 (Invalid operation)" message that spams every 5/10 seconds. (Most likely from OptiFine)

2. When just Immersive Engineering is installed:

• There is a problem where I can see certain parts of caves when I look through the surface of water.

3. When just OptiFine is installed:

• No problems or errors.

Full List of Mods:

• Forge (35.1.29)
• OptiFine (HD_U_G5)
• Immersive Engineering (4.1.2-129)
• Applied Energistics 2 (8.1.0)
• Industrial Foregoing (3.2.7-7d95990)
• Titanium (3.2.4)
• Mekanism (10.0.18.445)
• Mekanism Additions (10.0.18.445)
• Mekanism Generators (10.0.18.445)
• Mekanism Tools (10.0.18.445)
  I know the "instructions" said to not say the latest version, but I downloaded these mods today, 01/03/2021, so they are all the latest versions of today.

In reverse order: the "don't say 'latest' for version" instruction means give a version number, don't just say "latest" alone because nobody knows what the actual version number is in that case. You're fine on that. However, Optifine is not supported.

In reverse order: the "don't say 'latest' for version" instruction means give a version number, don't just say "latest" alone because nobody knows what the actual version number is in that case. You're fine on that. However, Optifine is not supported.

Yeah I was just mentioning it. Anyways, even with optifine not supported i mean i can deal with turning off OpenGL Error messages. It's the other problem I don't like which happens even when optifine is not installed. I will share a screenshot below.

In my original post I said "I can see certain parts of caves when I look through the surface of water." However, I think it's actually water/lava in caves and not just random parts of caves.

Actually I just figured out the problem. OptiFine actually doesn't seem to have a problem for me other than the fact that if I turn the Graphics setting to "Fabulous!", it causes the problem in the screenshot I sent previously. Any and all other setting changes do not have problems or conflicts as far as I've seen. I had to reinstall everything to figure out what the problem was between the two mods.