When using the "/summon FallingSand x y z {Time:1}" command, you cannot see the sand as it is falling, you can only see it after it has landed and become a block. I tested it in previous versions and did not have this problem.
MC-49007
Falling Sand Entity
Resolved
Duplicate
0
Larry Neuhold
(Unassigned)
Unconfirmed
Minecraft 14w07a
Retrieved
Duplicate of MC-48476 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.