I'm not sure if some of it was intentional or already known, but I've noticed that when I activate Lightspeed and then immediately go to use my next spell, Lightspeed's effect doesn't work for that first spell. The delay for Lightspeed's effect to activate is too long.

It's the same for Benefic II's special effect from Benefic. The free cure effect. When I use Benefic and then immediately go to use Benefic II as my next spell and I happened to get the free cure effect from Benefic, it doesn't work. It still goes through the cast time, but it gets rid of my free cure effect regardless.