These sorts of days (where nothing happens) happen.  If you had to bet on a day of the week and a time of year to see them, Summertime Mondays would probably be the safest bet.  Overnight volume was almost nonexistent, with much of Asia closed.  Domestic volume and volatility was effectively nil with today's trading range falling easily inside Friday's.  

On a positive note, despite the low volume, any day where bonds begin a new week holding onto gains from the end of the previous week is better than nothing.  In that sense, the fact that yields remained well under Friday's 2.937% ceiling in 10yr Treasuries was better than the alternative.  That said, I'd look at it more like an unofficial 3rd day of the weekend than a new and meaningful trading session.