Gilgamesh not taking damage? WTH??

I need HELP! Gilgamesh is not taking damage but his hits only give 1 damage.. I'm sooo confused. Is it a glitch? His health is at half and there is a symbol on it (🚫). I tried Google, YouTube, Reddit and found no info. I'm at a loss, I been just fighting him for the last 20 minutes and nothing is happening. He just keeps hitting me with the Legenderpy Strike taking -1 damage from me, my hours and magic do nothing 🫨.. Has anyone else dealt with this and what did you do to beat him?? Also I'm level 48 I think, I can't check while paused.

I need HELP! Gilgamesh is not taking damage but his hits only give 1 damage.. I'm sooo confused. Is it a glitch? His health is at half and there is a symbol on it (🚫). I tried Google, YouTube, Reddit and found no info. I'm at a loss, I been just fighting him for the last 20 minutes and nothing is happening. He just keeps hitting me with the Legenderpy Strike taking -1 damage from me, my hours and magic do nothing 🫨.. Has anyone else dealt with this and what did you do to beat him?? Also I'm level 48 I think, I can't check while paused.