Ask when the timestamps are made. Our log stamps entries after the file operation, which makes it poor evidence of what waited before the write. Do you have separate read and display timings?
Then don't call that a connection outage yet. A saved-input replay with a slow writer could show whether the application freezes without a network involved. The developer should time the stages independently of the writer being tested.
David's replay is the check I'd ask for. Also have them show what a genuinely old reading looks like; a frozen green box is not a useful status description.
And include the case where writing fails completely. Otherwise they may repair the delay and leave the screen looking happy while the log has stopped saving anything.