1) Trying to shear undead leaves is glitchy: They appear to disappear without dropping, but when I then tried to climb the tree, I found myself trying to press through invisible sort-of-blocks. (They didn't completely block me, but didn't let me through either.)
2) After bottling a thunderstorm at a dark temple, I took some odd damage, but attributed it to a nearby skeleton. But after flying home (out of sight of the temple's beacon), the accumulator's power bar keeps appearing, especially but not exclusively when I look in that direction.
The first one seems like a bug.
The second one does not however. The more you use an Environmental Accumulator, the more 'degraded' it becomes, and it will then cause some random bad effects like damaging all entities nearby.
The power bar that keeps disappearing is a MC bug, this should be fixed when Forge updates past 1.8.0.