Happened to me now too for the first time in the A319. Im at the latest update in the updater.  I have the whole thing on video if it helps.   Basically what happened is:   I made planned the flight, inserted all the stuff into fms and departed. Already here i saw that it doesnt move to more that 192 kts until FL40 and wondered. At some point it released though and it climbed out for a few k as normal ( i think). Then i was in outside cam and didnt look anymore what happens.