Release Versions 1.4.5 and 1.4.6 are out of order

Cannot confirm; however there was a previous ticket about this (MCL-2160). The release date of both version is the same, so the behaviour is probably unpredictable and dependent on the OS here?

I don't remember this glitch on previous versions of the launcher. I think it's just in the current version.
One possible solution would be to set go into the JSON files and set the releaseTime field of the newer version (higher version number) to one second after the releaseTime of the older version (lower version number).
Alternatively, use 7Zip to open the JAR file itself (do this for each JAR file who's date is the same but time is different), and then look inside its META-INF folder. Look at the "modified" dates/times of the files in META-INF, and notice the time (accurate down to the minute). This is the date and time that that version of the game was compiled. Use that date and time for the date and time info for the release time field in the JSON file for that version. Do that for both of these JSON files (the one for 1.4.5 and the one for 1.4.6). These changes may also need to be made to the main version_manifest.json file.

Unfortunately, this is not something I can do, as any changes to JSON files done by the user are automatically overwritten by the launcher when starting the launcher, and the versions_manifest.json file is never present on the user's computer when accessed by the launcher (only present on Mojang's server). Therefore, I can't do any JSON fixes. That's something that Mojang will need to fix.