There are four items that float outside of the hand rather than being grasped. Perhaps they have transparent pixels? Affected items include: Charred button, charcoal bit, glass shard, and goggles.

I use Item Model Fix which affects the rendering of handheld items. I also use First Person Model which makes this issue highly visible. If you have any trouble duplicating this it's likely related to those two.

Here is a screenshot of a charred button followed by an oak button for comparison:

Floating charred button

Gripped oak button.

Just figured I should confirm that it isn't a compatibility issue. The problem persists when I disable First Person Model and Item Model Fix.

Looked into this and it seems like vanilla items are like this as well, for instance iron nuggets and other small items float off the hand when viewed in third person. Buttons also do this for me, so some other mod you have installed might be fixing their models.