Board Thread:Lore Discussion/@comment-73.221.210.209-20150915184314/@comment-78.16.67.210-20150923180940

Since Serana was born during the first Era I believe she knows all about Dragonborn,and has seen some in her life line.Maybe she has seen some Dragonborns from other Eras,and is not really interested in the last Dragonborn absorbing souls since seh may have seen it many other times.

Either that or Bethesda forgot about Seranas 'OH MY GOD!!!' interaction