From report at FTBTeam/FTB-Omnia#97:
Issue: Log spam. I talked with mekanism dev, this is tesseract issue. Mekanism only warns about badly implemented inventory handler

tesseract-1.0.4-mc1.15
Minecraft Version: 1.15.2
forge-31.1.87

I can't reproduce it, so I assume version 1.0.6 might have fixed it.