iSRO alchemy bug!?

[ubnub96]

So toady i bought 24 8D challenge stones (crit) for plussing my 64 sun 2h with crit 5.
I first successed and got my crit 5->2 then i failed 7 times and then I successed 17 times and I got 17 times crit 2->2.
WTF!? I know that SRO's alchemy fails so much but i got 17 times 2->2 !!!!
How can that be possilbe!?

[Nova1337]

Critical is the hardest stat to change. Get used to use tons of stones and achieve nothing.

[ubnub96]

Yea, but in the end I got crit 10, enough for me =P

[donkey12345]

200 challenge tabs used to fix my crit on nova+9 daggers ( only 61% -.-)