It*does* flicker afterwards (e.g. 0.5 sec after I depress C-v), because
that's what deferred jit-lock does: it applies syntax highlighting with
a delay. So I type, wait 0.5sec, and syntax highlighting arrives. It's
a less-aggravating kind of flicker because of its laid-back pace, but I
still wouldn't call it acceptable user experience.
And in theory it should be possible to make something like
(setq jit-lock-defer-mode 0) avoid this flicker because the last
repetition of `C-v` is executed with `input-pending-p` returning nil, so
we should be able to fully jit-lock right away with no deferral at
that point.