Coit. We do indeed see such things. Many times there are TAs's in the 380s 390s. It seemed to start with the De Icing issues out of Tassie in the mornings but recently the speeds have occured again. Some of my minions have asked the crews and they claim it is economy speed. Always in 7 or 800s. Sometimes these speeds are actually flown and when a QFA 800 73 gets behind you and has 50 or so knots closing it becomes very obvious.
QFA sometimes plan not above M.68 and F260 but more often than not go above that level and faster with no revision of the plan.