Thanks for flagging this. I missed the patch note. This is working as intended and resolved a previous bug allowing the stacks to carry over. We have updated the patch note according.
Since ESO Direct is on the 10th "available on the 10th of April" is not the same as "sometime after the ESO direkt". Or do you mean right after the ESO direct.On April 10 sometime following the ESO Direct. (Depending on when they go up in the store after the livestream and what timezone you're in, I guess it could be April 11th.)