When you use an ability while placing a spell the spell will lose it's telegraph making you think that it's canceled.
Um... I don't understand. You mean, if you are dragging a spell into the play area and hit like... 1 to use the first ability in the slot?
No just regularly if you use a spell and the animation of a skill is still going while setting up an AoE spell you'll lose the telegraph. It's not a big deal. Unless you had like 10 seconds left on the clock and you wonder wtf happened to your spell.
I only cared to re-try it once in campaign with Bokor and chains of corruption. Or, I mean uhh.. Binding chains. Bokor + Binding chains. Actually I got it right the first time. lol