commandblock

bug:
when a minecart_commandblock with the clone command rides along a activator rail, and inside the cloned area there also is a commandblock-redstone clock. my game crashed.
the exact commands were:

(minecart_commandblock):
/summon MinecartCommandBlock ~ ~ ~4

{Command:"/clone 1213 4 730 1207 8 734 ~1 ~2 ~-2"}

(comandblock in cloned area):
/setblock ~1 ~ ~ redstone_block 0 destroy

i hope this was something on my computer or something, but couldn't figure out what it could be.
hope this will help a little.

thank you!