Fight with Alduin glitch?

[Kizenku]

So I'm fighting Alduin on the top of the mountain after reading the elder scroll (which I already had for some reason, possibly because I did Dawnguard) and he's not taking any damage. Nor me, my companion or the other dragon is getting his health down one bit, despite using Dragonrend!

Anyone else experiencing this? Any fixes?

[Volunteer]

My situation exactly and I am stuck. VGC no difference. Totally stuck on this one.

[Solomon Hawk]

You had to do a quest to get a specific elder scroll. Once obtained, you learn Dragonrend after seeing the vision of how the ancient nords first banished Alduin at the Throat of the world ... where you're fighting him now.

All Dragonrend does is force Alduin down to the ground (as it will with any dragon). It doesn't cause any physical damage.
Once Alduin is on the ground, use weapons or magic on him. Keep him down by re-using Dragonrend every time it recharges. I used the Staff of Magnus (drains magic) and an ebony war axe but melee, ranged, shock, etc will get his health down until he stops the fight near defeat. He then escapes and you have to track him down on another quest.

I've had no problem at all with Alduin at the Throat of the World.