Wither breaks Obsidian

I have found a Bug or Glitch in Minecraft 1.19.50 If we spawn any wither in Obsidian room though obsidian has high blast resistance it burst and wither Blast the obsidian and it may work as illegal obsidian farming and wither can break down obsidian is too bad because obsidian is a single item that have high blast resistance and we can get it in to survival so hope you fix the bug or glitch