I'm not worrying, and even if the output does have a bit of ripple on it, either it will be too small to matter (most likely) or I'll shove a simple RC low-pass filter in. But it's one of those, to me, "I wonder how that works, and if it explains an otherwise unexplained effect that other people have reported?" questions. Anyway, I'm on holiday at present and have only theoretical puzzles to worry about until I get back to the workshop and finish off the new control cabinet.