Just wanted to put this out due to the rule changes hoping it would benefit the public:
The initial treasure chest event gave wonderful opportunity of collecting upto 25k coins (in combination with daily coin limits and based on which limit you fill first).
The second chest event though short was also good allowing to collect 2 chests/ 6 hour with coins based on your level. The 6 hour restriction put limit on how many you can collect and allowed only to collect 3 sets for normal public assuming one 6hr set would get missed due to night time.
This time, the restriction seems to have been tightened further with the limit being set to 1 chest limit every 6 hour which means less coins and being able to collect 3 chests in a day on an average! Further based on the pop-up message on app load, we are assuming it is just a single day event!
So, don’t forget to collect each of the chests every 6 hours
Update (23-Aug-2018): As of 9am US EST, the current treasure chest event is over.