Electrical bleg

Okay, I pretend to know everything, but once in a while I'm out of my realm. As I mentioned in this post a few months back, I lose a little control over my lower GI when I'm working with electricity. Despite that, I managed to wire up some landscape lighting a couple of months ago. This evening a line of thunderstorms moved through the area, and it got dark enough to kick on my new landscape lights. But every time lightening flashed, the landscape lights flickered. The wire for these lights is buried, but it is insulated wire. Additionally, this is the first time this has ever happened during a thunderstorm. Is this something I should be concerned about, or was this just the result of ground that was highly charged tonight? Any thoughts would be appreciated. Thanks.