The Battery Boxes have a 1 Item Limit instead of a 64 Item Limit, InvTweaks does not seem to like that, but nothing I can really do about it.
As for your Solutions:
- That is 100% InvTweaks Side.
- Also 100% InvTweaks Side.
- They are intentionally stackable when empty, just like IC2 Batteries. Also have you tried Ctrl+Clicking anything else that ISN’T a Battery into this? I bet the same freeze happens.
And I don’t even delete anything that surpasses the Stacksize, so the voiding is also purely InvTweaks side…