People in Classic Era have noticed that the coin and bijou drop rate has been significantly reduced for months. See this thread.
In order to produce more than anecdotal evidence, I ran a ZG and master looted all coins and bijous to myself while also logging the run. The total number of coins/bijous that dropped were 21/3. For each “UNIT_DIED” event in the log, I looked up the loot table on wowhead and accumulated the expectation and variance for the number of coins and bijous.
For the 213 mobs that could drop the items, the expected totals are:
Coins 69.5 +/-6.3
Bijous 44.8 +/- 5.7
The actual coin count of 21 is a 7.8 sigma result. The actual bijou of 3 count is a 7.4 sigma result. If the drop rate were normal, there is less than a 1 in 10^24 chance that this single run would produce so few coins and bijous.
Please fix this issue.