I'm using CCleaner Pro version 5.55.7108 (64-bit) on Windows 10 Pro (64-bit) Build 1803.
The new Software Updater indicates that there is an updated version of Notepad++ (126.96.36.199.0 > 188.8.131.52.0) available for my PC.
This is correct.
Unfortunately, Software Updater incorrectly downloaded the 32-bit version of Notepad++ instead of the 64-bit version needed to update the existing 64-bit install.
Thankfully, the Notepad++ installer flagged the issue before proceeding with the install.