Ok, so I found out what the issue is, and I have a temporary fix. The issue is that the launcher isn't actually updating the "installedPacks" file (an unlabeled JSON file). To force the save open the file in a text editor (Notpad ++ is what I used, idk what other editors will work, but most, if not all should) and replace the directory that is specified for the desired pack with the desired directory.
Note: all back slashes (\) must be double back slashes (\\) so C:\Users\Name should be C:\\Users\\Name
I hope this is fixed in the next few builds, it should be relatively simple.