My team has been quite lucky injury-wise for weeks until I gathered over 100 red packs. Then injuries started popping up daily, 1 or 2 players per day. Fortunately I don't have any big games ahead, so I just relax and don't heal, as long as I have enough decent substitutes. Have I crossed a magical barrier of 100 red packs, I don't know, but if this is some kind of pressure aiming at making me use all the reds, I simply won't do it.
This is not the first time such thing happens and as far as I know, there is no known solution to this.