Update 7/13/2021: It looks like this got addressed in today's patch notes:
"Corrected a bug that would cause items that had two spiritstones added to them to crash the game client when the item was examined."
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The new Heart of Luclin spirit stone has been reported to crash some players, sometimes, when they examine the item or a piece of gear that it's been added to. There is a mechanism that adds an effect to the window depending on which level you are previewing (adds the effect at level 10), but looking at the custom code there should not be anything preventing it from displaying correctly.
I don't think it's a custom UI problem, but just in case I've made a speculative change to the Examine window. The new version is 3.010. Please update and let me know if you experience the issue. Thanks!