Messages

It seems they are trying to be "clever".
Because you rename the executable to a consistent scheme it fails with a "corrupt installer" error.

If you rename the "corrupt" executable to "SumatraPDF 3.4.6 (x64) shitheadinstaller.exe" it installs successfully.

I downgraded my install and the new version of PatchMyPC has upgraded it correctly.

+1

PaytchMyPC says I "might" have two versions of 'Git' installed and refuses to update it automatically.

If I go to the uninstaller tab there is only one install of Git listed (as expected), however, I do notice that it's listing "Git Extensions" there: https://github.com/gitextensions/gitextensions
This is an addon to Git that installs git.

Git Extensions 2.49,2.49.00,Henk,MsiExec.exe /I{79DDC732-E58F-4ACF-B9D5-2413C9E5C917},02/21/2017,
Git version 2.11.1,2.11.1,The Git Development Community,"C:\Program Files\Git\unins000.exe",02/21/2017,

When I tick 'git' and force an install it installs the 32bit version side-by-side with the existing 64bit version

After this there are two versions installed, but only the old 64bit version is visible from the Windows10 "craplet" version of the windows installer interface. Both versions are visible from the control panel version "Programs and Features".