So, I was looking at somethings with replacing the Psychic bloodline with the alternate capstone, Unique bloodline. One of the options I was looking at was Arcane bloodline, that has the third level power get replaced by the 20th level power at level twenty.
So I'm trying to figure out what happens with the third level power. Does it upgrade, disappear, or just stay the same?
Since you don't get the 20th level power it can't upgrade to it. I can't imagine it'd disappear in a puff of logic. That leaves staying the same.