I have notices over the last two days I have not got a single event challenge. I have tried finishing regular challenges and even used like 5 or 6 swaps but nothing works. In upcoming challenges it shows event challenges but they never show up and we only have like 20 hours left 
Unfortunately, this is a glitch people counter apparently. I dont think there is a way to fix it.
It almost stopped me from getting the Kabuto helmet… almost.