Hi Comm,
I'm using SCCM 1802 with all hotfixes and after serveral wsus syncs, there are some updates missing for x64 or x86 architecture. In my case I need the 1807 (10325.20118) Update for x86, but it's only the x64 version available.
I've never seen this before for other products like older Office versions or Windows in my environment and found no known issue for this.
Has someone an idea or seen this before?