Forge, version 1.19-0.3.20.57

When broken (regardless of whether or not the player was sneaking), lootr shulker boxes do not play a sound. They still play a sound when the player is in the process of mining them, but finishing breaking them does not play the usual stone break/place sound. Unlike the barrel issue (#228), this is not reflected by sculk sensors - they activate when a lootr shulker box is broken nearby despite the lack of a sound. The barrels, chests, and minecart chests all play their proper sound when broken, the shulker box is the only one missing it.

This is because event 2001 which calls the soundtype.getBreakSound() isn't fired for some reason. Looking into it further.

This has been released for everything except Fabric 1.19.0.