Same experience for me, and in fact I had the brain-zapping withdrawal symptoms while I was taking a steady dosage. The zapping happened with both Zoloft and Lexapro. It happened regularly many times per hour.

When asked to describe it, I tell people the zapping feels like my mind is lost for a fraction of a second. For that tiny moment I really think I'm completely non-functional, and the thought of this condition lasting for a non-trivial amount of time is frightening, although I've never heard of that happening.

Zoloft was beneficial for me, but not enough to outweigh the discomfort of the brain zapping.