In an optimized Project Ozone 3 instance (Cleanroom Loader), using LoliASM makes hidden items (eg. AE2 facades) appear in HEI. Removing LoliASM fixes the issue.

Without LoliASM:

With LoliASM:

If you have some time can you try disabling one of the nbt tag related optimizations and see which one affects it? Thank you for the cooperation.

nbtBackingMapStringCanonicalization and optimizeNBTTagCompoundBackingMap are the cause. I had to disable both, disabling one or the other didn't fix the issue.

Got it, will address this.