Orangetsu

Before starting dawnguard go catch sanguinare vampiris than before it turns you into a vampire start the dawnguard quest and before you enter the cave let the disease turn you into a vampire, this should fix the problem of turning back into a mortal after using the vampire lord spell. That should be obvious the one that the leader of the dawnguard sends you too. I don't think my fix works with custom races or races that use to be custom but changed back to vanilla.

just follow the questline like you should the goal is to be a vampire before you are turned into a vampire lord

Before starting dawnguard go catch sanguinare vampiris than before it turns you into a vampire start the dawnguard quest and before you enter the cave let the disease turn you into a vampire, this should fix the problem of turning back into a mortal after using the vampire lord spell. That should be obvious the one that the leader of the dawnguard sends you too.

It worked for me so give it a shot, Before starting dawnguard go catch sanguinare vampiris than before it turns you into a vampire start the dawnguard quest and before you enter the cave let the disease turn you into a vampire, this should fix the problem of turning back into a mortal after using the vampire lord spell.

Before starting dawnguard go catch sanguinare vampiris than before it turns you into a vampire start the dawnguard quest and before you enter the cave let the disease turn you into a vampire, this should fix the problem of turning back into a mortal after using the vampire lord spell.