Minecraft Hardcore hearts changed from "hardcore hearts" to "normal hearts".
This is a well known Minecraft bug. Only the texture changed but the server is still hardcore.
Link to the Minecraft bug: https://bugs.mojang.com/browse/MC-180042
One of our anti-cheat plugins do make breaking of certain blocks harder.
Those blocks include: crafting tables, beds, doors.
Also, sometimes you might get teleported under the boat when you are trying to ride it.
We are waiting updates to fix those bugs on the plugin.