Two possibilities: your cycle had not stopped entirely and you were surprised; or, some (few?) folks find that they cycle so rapidly that staying on Verap. full time is an effective/needed response.

There have been some docs who keep their CH people on 100%. But there is no indication, in the medical literature which I've seen, that the med itself somehow acts to sustain the CH cycle. Given its benefits to us, it's a rather benign med.

    I took Verapamil 480/day before my heart surgeries. Haven't used it since because my BP tends to run low. So I just use Dopymax for a prevent these days.
    When I was episodic. I used to go off of it every July without any problem. That stopped when I turned 50. When like 15% of the middle aged men I turned chronic. Then I had heart problems at 54, and couldn't take Verap. anymore. I liked it, cheap drug, easy to tolerate, did a good job. At least for me.