Mind Spike is cast with one action but has concentration up to an hour. Unless I'm mistaken, the actual casting process of the spell does not take concentration, due to it not being longer than a single action. Ending concentration is a non-action that can be taken at any time. Would it be possible for a player to cast it but choose to not concentrate on it after the initial damage, thus not breaking concentration on another spell?
The main reason I'm wondering this is because Mind Spike is the only weaponized Divination spell, and actually scales with higher slot levels. I could see this being used to get the most out of a Divination Wizard's Expert Divination class ability.
It makes sense that this would be possible to me, but I'd like to know a more concrete ruling.