That's because you first installed ESET using a bootstrapped installer which in fact runs an msi installer in the background. The msi installer is then kept in c:\windows\installer folder and is run if you choose to repair the installation.
Since upgrade to newer versions is typically carried out via uPCU updates (ie. not the whole msi installer is downloaded and only differential files are), the repair feature of the msi installer cannot install the very latest version to which you've upgraded via uPCU. Moreover, uPCU upgrade is typically performed throughout various versions, e.g. 11.0 (bootstrapper / msi) -> 11.0 (uPCU) -> 11.1 (uPCU) -> 12.0 (uPCU), etc. We had been considering disabling the repair feature for this very reason in the past.