Everytime I bring home a mrs.garfield amaryllis(and any other amaryllis) , i repot it then water then i place it in a sunny spot.After a few days all their leaves turn from very dark green to light green,but they continue to grow new leaves(all light green) and bloom but the leaves never turn back to dark green.my other amaryllis never does this.not even the other heavily variegated ones.I give all my amaryllis the same care.what could be going wrong?