A bug or worst luck ever?

Is the NPC for slotting Undershirt working?

 

with this week's TI, i got a little over 60 Undershirts.

I tried to slot 60 of them in a row and all failed.  And in the past i tried to slot maybe another 20 or so, (on and off whenever i had some in storage) and never been able to make a single one.

(so a total of a little over 80)

 

I go to the NPC in Prontera Upgrade Shop.

could be terrible luck; someone more mathematically inclined than me can run the numbers on the odds of you failing 60 in a row.

I don't know if it's a good news or an irritating one for you, but I've turned around 20s Undershirt and got around 3 slotted ones from them.

I've cross-checked Ragial and I was vending it around September. Should work fine.

Just horrible luck. It took me like 40 at least to get my first one. The rate is only 5%, so the variance will be huge with a sample size of 60

wow... u tried 80 times which cost you 80 million and gets nothing?   I've tried slotting memory book and stunner a few time and couldnt stand anymore seeing those things exploding on my face. I now consider this slotting option does not exist   and do not bother to try again

Well technically, you should get 1 in 20 if it's 5% chance, I got one on my 7th try the first time I tried and 1 out of 20 in total, I stopped after 20.  

Some people have good luck, others don't, such is RO life.