A player (John) has the Queen Bee Unicorn card in their stable. The effect of the Queen Bee Unicorn card is that basic unicorns can no longer enter the stables of other players:
"Basic Unicorn cards cannot enter any other player’s Stable."
Another player (Jane) plays the Pandamonium card into the John's stable. All of John's unicorns are now considered to be pandas:
"All of your Unicorns are considered Pandas. Cards that affect Unicorn cards do not affect your Pandas."
The Pandamonium card is a downgrade card. It has a pretty powerful downgrade in that a player with it in their stable would be unable to win (since they need seven unicorns, not pandas).
However... does the Pandamonium card cancel out the effects of the existing unicorn cards? Does the effect of John's Queen Bee Unicorn card cease simply because it's now a Queen Bee Panda? Or does the effect continue?
NOTE: I would suggest from reading the descriptions that the effect would continue. But does anyone know? or have thoughts?