Not sure if my issue is related to this store patch or not. I have noticed my launcher seems poky and sometimes I have to force shut it down. I double checked after seeing this thread and so far I only have one .tmp file in my DCCache. My overall DCCache file is only 2.31 KBs at this moment. Many others here seem to be reporting a much larger file.
The one thing I did notice in-game is when I go into CAS now I have doubles of many "downloaded" items showing up. Many of them are Store content.... like clothing. I hadn't noticed that prior to the patch.
Anyway, not sure if my item is related to this patch concern discussed in this thread or an unrelated issue. BTW, I do have Overwatch and MasterController. No 3rd party content, only Store Content.
Edit: I checked and my Download Folder and it currently shows a size of 10.3 GB, that's all Store Content. :)