I've heard the same, but never inside EK. The interesting thing is that if it does, the means is unclear except for the following possibility...
Just as Sodium Sulfite -> Sodium Sulfate in hypo solutions, thereby protecting hypo from oxidation, the Selenite might do the same thing and the Selenate is less toxic, but IDK by how much. And, since I don't want to work with it, I have not run, nor don't intend to run the tests. I was exposed to lots of Selenium Dioxide in grad school making alpha-diketones. After listening to stories at EK and finding their reluctance to get into Selenium sensitization and Selenium sensitizing dyes, I am a bit too negative about Se.