Place a redstone ore block. Next, stand on the redstone ore block or right click it so that it lights up. Spigot will then produce an EntityChangeBlockEvent, even though this event isn't supposed to be called for player entities.
I think this was an oversight, see the CraftBukkit patch https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/browse/nms-patches/BlockRedstoneOre.patch#67.