Originally Posted by chillinfar

Only experience from past perogambit. Kil stopped to be summoned at some point.

In fact, this cycle is notorious since 1st perogambit. Just wait until tomorrow or review some old posts.

I just got one again in the second part of the event. Keep in mind that if you max her to level 100, she will no longer appear in the boxes (source: Nutaku response to a ticket, see previous page of this thread).

Originally Posted by JSensei

I don't have data to prove it, but I will bet that the drop rate is variable. I'm guessing it's probably like the rate of chance time on extra stage. It probably fluctuates according to some set schedule that we are not privy to as opposed to being a flat x% rate all day. This would help explain why she tends to appear in 'clumps.' I've noticed other people say that they got her back to back, too. We can know as much about the base percentages as possible, but I'll bet almost anything that everything is variable according to a master schedule.

I posted that before EvilAngel pasted the support tickets responses. Nutaku said they increased the chance TWICE because it was too low (possibly due to some bug they couldn't find) so in this case, the drop rate actually changed.

Originally Posted by Vic47

+1
For example, I sometimes spend alot of NGacha tickets (50-70+), and don't get even a single SR, while sometimes i spend only like 8 Tickets and get one for the 1 SR Daily Mission. I also pretty often get those near the Dailies restart time (2 AM for me) - at like 1:40-1:50. Same goes for Triple Rolls (Exp, Pero, Etc.) Sometimes they come one after another, so i complete teh first two stages of Dailies consequently, while at the other times i can't get a winnig roll even spending my full 300 Sta even on GHQ (at least, the ones i need atm to complete the last mission i want). Or i can get like 3 SR cards on Ngacha while doing N or R cards Daily mission, but as soon as i subscribe to "Get 1 SR girl" Daily Mission they just stop spawning. Also, today ive spent like 150 Ngacha tickets to finally get the new N slayer before starting to spend my Stamina that i've accumulated while i was sleeping. Almost the same shit Ngacha was doing on me te last time when i've tried to get the 1st phase N Slayer, before starting to roll the gambit slot machine. So yeah, looks like it's not a constant chance % n everything, but some hidden schedule, just like the Sunday Rotation Schedule on GHQ.

This "sometimes" and "sometimes" thing you describe is really called a random. You can get something in your first try or you can not get it after 500. That doesn't mean the rate has changed. People in general tend to find/create explanations for things that are either not consistent or they don't understand and it has been proved scientifically. It's how the human mind works.
Think about it. What would be the point from the game developer's perspective to put increased/decreased drop chance based on time or any other factor? It's just pointless, doesn't make any sense and requires more work. And even if it was real, things like that should be known to the public from the very beginning.
HOWEVER, Nutaku is very unprofessional and it wouldn't surprise me if they MANUALLY, silently changed event items drop rate from time to time.