Lava not being picked up

I was playing survival on a creative world and make a bucket to pick up lava, first time I picked up lava it took away the source block but did not put any lava in my bucket. Second the client put lava in my bucket and took away the source, but the server was not updated and when I tried to place the lava it went away and the lava came back. The third and final time the server and client communicated and it worked.