My CF has been at the same level for a few months now. I can say that big picture, it is truly random, but I will find it goes through cycles where I get one reward a lot, another nearly never, then it will change the next day. On a single day, chances are you are not going to find your results fit the data others' have. But, since it is random, you would have to monitor it for a long time- months at minimum- before you would have the data to support a change.
Murphy's law or whatever, but I find I never get what I need. A few medals shy of an expansion? I can do 20 UBQs and not get medals once (yet another day I seem to get nothing but medals.) Need coins or supplies to finish my other RQ slot, a DC, or other quest? I get the opposite (this is the case with incidents, too)
I must be getting everyone's FP packs because across all of my worlds, I've gotten a lot in the last week ago. The other day while collecting (RQ set on coins and I did the UBQs) I got 6 FP packs in a row. When the third came up, I started actually counting because it was unusual. (This was out of about 10 quests- 5 coin, 5 UBQ)