Jasco 3-Way switch (45614) sparking?

The z-wave commands never seem to make this happen, but I noticed before I buttoned up my new 3-way switch that pressing the physical button on the master switch, causes a minor spark on the line connection point. Happens about 10% of the time. Anyone else seen this? Have any suggestions?

House is 4 years old, I have all the neutrals/grounds a person could want.

Thank you.

Cheers.

The neutral wire was a bit loose. I tightened it down and after 40 tests, it never happened again.