A couple of points on this. If you overtrain kegels, you can experience side negative effects that could interfere with your erections. There are many accounts of trainees who abuse kegels and experience effects like "hard flaccids", spasms, premature ejaculation, and issues with their EQs- to name some.
Now, there are technical aspects of the kegel can lead to issues if your training is unbalanced. When you kegel, you're contracting the muscles of the PC- and this affects the penis directly through its attachment at the pubic symphisys. This is why, during an erect kegel, you'll notice your penis raise each time that you contract. If you're doing your kegels erect, you'll counter this effect somewhat (with some equivalence of stretching against the contraction due to your penis being erect). If you consistently kegel unerect- especially if you have poor EQ- there's no effective counterbalance and you may end up toughening your ligaments without making them more flexible.
Over time, training in this fashion may [theoretically] lead to some loss in length, or at least more resistance to your gaining length should you decide to take up lengthening training afterwards.
To fully counter this effect, you should do your kegels erect. This will also help you get the most out of your kegel training. You may also further balance your kegel training with stretches. This will ensure that your ligs develop a well balanced maximum of both flexibility and strength.