Unless I see K and Na together, both in elevated levels, I don't worry to much about it. Both can be additives in some lubes, so you have to understand the VOA starting point.
If you don't have evidence of coolant disappearing, and you don't see significantly elevated levels, I'd not worry about it. The greatest concern would be to see ever-increasing levels. If your levels are steadily under 20ppm, with no coolant loos, I see no real issue with that.