What might keep Serana from adding her blood in the Portal Vessel during Chasing Echoes (Dawnguard)

During the Skyrim quest Chasing Echoes, from the DLC The Elder Scrolls V: Dawnguard, after adding the ingredients in the Portal Vessel, I couldn't get Serana to add her blood in the Portal Vessel like she said she would. After she says she'll add her blood to ingredients, a message is displayed instructing to add the ingredients, so I went to the Portal Vessel then activated it then ingredients appeared in it then a message instructed to speak to Serana, which I did and when I did the dialogues which I though might be related I searched for how to complete the quest point (of speaking to her), well... there was a plethora of related bugs so I looked at some of them. I reloaded the previous save hoping that would fix the issue, I ended up in pretty much the same situation, so I though I'd go through all the dialogues, even those I though were not related and ended up with

and since the last 2 inactivate/unused/unspoken dialogues are related to non-quest mods, the only remaining was "Come with me." which after activating she let me know I should get rid of my follower, which was a pet in my 2nd slot, from Nether's Follower Framework (NFF), which I was surprised since she had the 1st slot. After having the pet stop following me then speaking to her, the quest finally went ahead and she poured some of her blood in the Portal Vessel. My PC ended in Soul Cairn, with the pet since I had it follow after the issue was fixed, so all is currently well.