Yes, it should be once per day, even if sometimes even that bugs out for me and I get more than one use per day. But if when I long rest after using the tadpole some companion scene or conversation triggers, then I won't get the dream, no matter what. If you play solo I guess you could never run into this problem, even if it was affecting you. Especially if you kill companions or don't recruit them at all. That's what made me think the problem may be linked to companion cutscenes/convos.
