So if you place an end crystal normally you can't place ant thing around it, its acting normal until you explode it. The crystal will be gone same with the blocks but the area you placed it in you will not be-able to place any blocks acting like the crystal is still there.
Can confirm this issue is still present in 1.14. Screenshots demonstrate how to recreate this bug
EDIT: It is also worth noting that the issue goes away when the world is reloaded
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