Difficulty settings have nothing to do with this. If OOO doubled the drop rates, it should double the average amount of drops received when compared to runs at the same level from before the supposed drop rate increase.
The drop rates of current Normal runs should be about double that of last week's Normal runs.
The drop rates of current Advanced runs should be about double that of last week's Advanced runs.
The drop rates of current Elite runs should be about double that of last week's Elite runs.
I am not basing this on one or two runs. I have been noting the drop rates of all the many, many Grinchlin Assault runs I've done. I've run a few complete missions under the new drop rates, in both Advanced and Elite. I am not seeing any significant change in drop rates. I have compared notes with other knights who have been running this mission. They have not seen any significant change in drop rates.
The drop rates have not doubled for Grinchlin Assault.
Perhaps you are unlucky and got less drops? Try playing on a harder difficulty, it affects drop rates as well. Don't make comments based on 1 or 2 runs only.