Red Acer Woes

In the last 6 years I have bought a red acer almost every year (one year I didn't).  Every time i bought them was in the summer (June-ish).  The next April/May the acer gets new leaves and looks really healthy and then without fail, by mid-May, all the leaves shrivel up and then the plant dies.  I have tried different positions in the garden each time.  I've moved house during this time.  I've tried in pots/not in pots.  Last year i bought 2 acers: one red and one yellow.  They are in identical pots next to each other, in a shady spot.  The yellow one looks amazing and same story again with the red one.  I tried googling it and I found several people posting on forums with the same issue, but the responses are always the same about either under-watering or over-watering or too much sun.  I don't think I have any of these.  At present, this tree itself looks alive as the branches are all still red.  I would love to save this plant but I cannot understand that this happens every year.  Previously, I had a red acer for 12 years and it was amazing, but it died because I had to move it (long story!).  Since then I have either been very unlucky or something else is going on.  Any advice would be appreciated.