With stackableShulkerBoxes enabled, trying to click together shulker boxes in an inventory will stack any identical boxes together, even full ones.

They should only stack if they are the same color and are both empty.
What currently happens is that they can stack if they have the same color and the same contents.

This just seems to be the same behaviour as other stackables with nbt have (ex. banners).

I believe this was introduced commit 3affa8d.

(This was on a server. I am using a few other mods, the only thing that could interfere is tweakeroo but all shulker settings are disabled.)

Oh thanks, i'm sorry then for creating a duplicate. Should have tested on the latest version.

And I believe that was fixed right after at 181bfb3

I didn't think that oversight was necessarily wrong just little too overpowered, so that was cleaned up.