The issue is this mod leaves a weird bright overlay in your inventory when used with Optifine. It's only when you place a build craft item like an engine, then you open your inventory. It's gone after getting rid of Optifine. This "overlay" bug also interferes with other mods like Journey's map.

Please complete the following information:

• Forge Version: 14.20.5.2854
• BuildCraft Version (Add Hash if from github): buildcraft-all-7.99.24.6
  Any additonal mods: Optifine

To Reproduce
Steps to reproduce the behavior:

1. Install optifine
2. Place a build craft item like an engine
3. Open inventory
4. See the overlay

Optifine was installed when making this gif

This is most definitely Optifine's problem. This issue has been happening to me for years on my entire hotbar. The last version I played with Optifine was 1.14 and it was still happening to me. There are certainly other issues that are presented with OF in tandem with BC, and this one may be made worse on some systems, but it happens to me without it as well.

Also, OF is closed source. There isn't anything that the BC devs or any contributors can do about this or any other OF/BC compat issues.

Example image of when my Optifine was doing this from 2018.

Also from 2018. I don't even use the same PC anymore, and it still acts the same as it does on this new one.

Out of curiosity, what happens when you try other oddly-shaped blocks from outside of buildcraft? I can't think of any off the top of my head.

I tried it with some oddly-shaped blocks from Galacticraft, Architecturecraft, and Mr Crayfish's Furniture Mod and nothing happened. It's only happening with Buildcraft.

I never knew that it could also break at random. I'm actually playing my own modded series and I came here since the issue only started around BuildCraft stuff only.

I might just remove OptiFine entirely since I have 16GB max 12GB minimum of ram allocated to Minecraft with my 12 CPU threads using an optimized Java argument from here https://hypixel.net/threads/guide-minecraft-fps-lag-2017.1218021/ and I have better fps installed.

Also since it has caused other visual glitches in the past on my mod pack, lIke Journeys Map giving me a blue screen when the overlays are there or when some mobs were invisible (this might be the reason why most big modpacks don't have OptiFine). Well I think I have enough evidence to know not just with BuildCraft and I think it's time to close this issue soon. Thanks Dame-E-in.