I am using the following command:
/blockdata 290 57 -436
{Text1:"{\"text\":\"Cursor\",\"bold\":\"true\",\"color\":\"dark_green\"}",
Text2:"{\"score\":{\"name\":\"@p\",\"objective\":\"CursorPrice\"},\"color\":\"dark_blue\",\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock 290 56 -431 redstone_block 0\"}}",
Text3:"{\"score\":{\"name\":\"@p\",\"objective\":\"CursorAdd\"},\"color\":\"red\"}",
Text4:"{\"score\":{\"name\":\"@p\",\"objective\":\"CursorAmt\"}}"}
and the sign that is being updated only shows the first line, and all of the objectives have values. The command block says it was updated successfully, even though all the lines except line one are empty. Note: the clickEvent also works