I am currently making a setup where a breaker seal breaks full jars of essentia. I made this setup in the End dimension.
The golem properly targets the jar for breaking and does so, but the jar seems to never be destroyed (the block does 'pop' each time the golem performs his breaking action). The jar neither drops an item.
And for some reason, this doesn't apply to the overworld. (I've yet to try other dimensions)

I have no idea why this occurs. Disabling ThaumTweaks does make the issue disappear. Likely something messed up when jars got a customname tag? But still it's really weird.

appears to occur even without ThaumTweaks.

When the golem first breaks the jar, it does drop itself as an item. The jar remains in place however. You can break the jar yourself to get another item, and the jar is properly broken. You can place the extra jar, and the golem can neiter break it, nor does is drop itself once.
The issue also seems to occur in the Nether.