Dacia Logan difficulty engaging gears

I had problems engaging gears when car had warmed up. Had to push clutch pedal fully to the floor to change gear and after a while I would not be able to get any gears. Stopping the car and pumping would make clutch work again for a few minutes then it would go again. Had the Master cylinder replaced recently and that seemed to solve the problem. I am now getting same issue again. Clutch does not slip and car pulls perfectly once gears are engaged. Problem seems worse in hot weather.