It looks like your server has intermittent issues connecting to the internet, which means that it struggles to download the updates. Sometimes it appears to work, other times it doesn't - OctoPrint's connectivity check also indicates the same patchy connection.
Do you have intermittent internet issues? Maybe a weak wifi signal where the Pi is located? Network issues is what you will need to try and debug with some testing there, maybe see if a wired connection helps temporarily.
The system info bundle you have says that it is running version 1.7.3, presumably they are still the correct files?