I'm Sorry, if it did not get activated tonight - There is mathematical absoluteley no question that it does not work! I mean its kinda easy: If the droprate of the tempering is 50% we can do the math: (the event description says the items can be dropped with 50% chance - so if there is a gamemechanic that somehow reduces the chance based on other drops, the description would be wrong since the chance is below 50% then)
Runs without Drop - probability for no drop (if the droprate is 50%)
1 - 50% (=1/0,5^1)
2 - 25% (=1/0,5^2)
3 - 12,5% (=1/0,5^3)
10 - 0.09765625% (=1/0,5^10)
15 - 0,003% (=1/0,5^15)
20 - 0,000095% (=1/0,5^20)
To be honest how can you denie these numbers? ppl did more than 20 instances without drop. In fact the probability for tempering EVERY of these runs is exact the same. I heared noone saying he dropped temperings 5 times in a row what has probability of 1/2^5=1/32= 3,125% - while there are LOTS of ppl doing 20+ Instances with 0 Temperings.
So the numbers sare easy - The question is: you dont trust the mathematics or the ppl that say they dont drop?
If its the Last thing - How many Instances do you want me to record on video without drop - until you believe what we say?