[Csnd] combinv strangeness or bug?

Hey hey,
I've been looking at the comb and combinv opcodes. It appears that the krvt parameter has no influence on combinv at all. To be sure I ran the manual example and noticed only one delay. Changing combinv to comb in that example yielded a wildly different resullt with multiple echoes.

Is that by design or a bug?

I am now running Csound version 6.16.

Best wishes,