I have several Windows 7 PC's with Wireshark x64 installed (install location: C:\Program Files\Wireshark). PatchMyPC detects Wireshark x86 instead (which is not installed). When the version of the x64 is outdated, Wireshark x64 is 'upgraded' to the latest x86 version.
Can you attach the PatchMyPC.log?
We were able to repro. It looks like their installer registers the install into the 32 bit registry uninstall key not the native 64 bit that is why it's being detected incorrectly. For now, the best option would be to skip updates for Wireshark.
(https://i.imgur.com/hLISM1j.jpg)
This was fixed in the last release of Patch My PC v4.1.0.0 :)