I would say that's a lack of accuracy, not precision. If it was less precise than it's work on more things, and be less focused on one particular thing. If it's more accurate than it is better at describing all targets.

Precision: Is your grouping tight.

Accuracy: Are you aiming at the target.

Precision without accuracy is you very narrowly describe what it does, but you miss the desired target (the player being able to use the spell in a reasonable way).