Find Usages doesn't find some usages

I have two classes (AccountHandler and DocumentHandler for example), and they both have nearly identical implementations of a method (ProcessAsync).  Inside that method I call a static helper method (ArchiveHelper.WriteZipArchive).  If I click one WriteZipArchive in either file and hit F12, it goes to the exact same file (which is located in a different project in the same solution). 

However, if I use Find Usages it will only find the usage in the DocumentHandler not in the AccountHandler.  Even if I say Find Usages with the cursor on WriteZipArchive while inside AccountHandler it still only shows the one is DocumentHandler.  

Is there anything I can do to troubleshoot this problem?