To expand on Mod Ramen's comment -
Ninja strikes are planned well in advance and the Grim pages stuff was never our responsibility at the time. We took it onboard because we had the schedule for it where other teams/personnel didn't.
We generally plan ninja strikes with our own big hitters (subjective to each person), so no we're not "holding it back to make it look better" and wouldn't want to do so anyway :)
For the past few months we've been busy helping support the wider RS team with the login lockout situation and delivered the bonus/event weeks and the guardian's gift (wishes) which is why you haven't seen a ninja strike in a while... but we're back to business as usual now!