For what it is worth, and on the assumption that your computer was restarted multiple times during the troubleshooting process, I can only speculate and due to a lack of data it would be more of a W.A.G. than speculation.
- Bad Kharma (high on my list of suspects )
- a startup item that either got turned off or updated somewhere along the line.
- A task, running in the background that eventually concluded
- a background task that was automatically updated without your noticing
- a corrupted scratch file that eventually got overwritten or replaced
Now maybe you can explain to me why H&R Block and one or two other apps refuse to update so i have to download and install the full app every time.