They just fixed the bug where already produced spells changed if was produced using one spells configuration and gathered using other spells configuration. Now only queued spells are changed when switching configuration. And even spells queue time fixes itself when new spells go into production. That should have been done before the first wave of migration to new tech tree, but was done only before the last one. it would be better if queue follow spell configuration changes, but now at least already produced things are not lost.