On a sample sizes of 1, RNG is truly random. No conclusions can be made based on it.
I finally got a booster at the end boss of the tower a few min ago.
On 1 account I run 80 wishing wells, there are weeks diamonds are limited and sometimes there overflowing but in general I get average amounts of diamond from them at least when I use the average of 10.000 harvest as a sample size. With a variation of 10?
In a good week the sample size of recipes is only 140 with a variation of many more (sorry to lazy to download a read the gamefiles).
This sample size is way to low to get an average. I am tracking the crafting feature since week 50 of 2018, and see plenty of good and bad weeks.
My worst streak of combat buildings in a week is 0-0-1-1-1-1, so 4 buildings in 6 weeks.
My best streak is 3-6-5-1-5-5, so 24 buildings in 6 weeks
I also got a nasty streak with 1-0-0-3-1-1-1-0
So bad streaks aren't unheared of and not related to "recent" weeks. this doesn't mean they might not have changed the formula somewhere in between. but I rather throw it at RNG than conspiracy theories