When using end crystals, their explosion is no longer "flat" What I mean with this is that they make an explosion more similar to that of tnt instead of the characteristic end crystal explosion that doesn't destroy any blocks beneath the end crystal .

Since you need obsidian to place an End Crystal, the obsidian blocks some of the explosion, so the blocks that are directly underneath the obsidian don't get blown up. You also seem to take more damage from the explosion if you are one block below it (where you wold normally blow up the end crystal to take as little damage as possible)

Steps to reproduce:

1. Get yourself and end crystal and place it on some obsidian (I recomend doing it in the nether since netherrack has a low blast resistance, but the bug works on all 3 dimensions as far as I have tested ), it can be done both in creative or survival
2. Destroy the end crystal, yo can do it with however you want, with your fist, with a bow, crossbow, etc.

Expected result: You get an explosion that doesn't destroy any blocks underneath the "y level" where the end crystal was placed
Observed results: The end crystal destroys blocks below the "y level" where the end crystal was placed

Note: I have tested it also on the betas/experimental versions, and the bug is still there