I would say so, that means the insulation has broken down, and the easiest path for conductance is anywhere but where it's supposed to be. You might not always see this, is the problem worse when cold/damp? or warm?

Keep in mind that sometimes the sparks arent always easily visible, so its not a surefire - an indicator.

If when the car heats up its harder to start with the engine warm, or requires a few minutes before it will start then that sounds like the coil needing to cool down in order to operate "correctly".

I had one coil fail so spectacularly you could hear it arcing (and crackling an awful lot) out behind the dash when you were driving or starting the car sometimes. That got changed quick snap!