Leaf decay and crop growing stops when new chunks load/player goes to nether

From what I can tell, any time someone starts traveling across the world (We've had at most 5 people on the server at a time) when new chunks spawn, and more recently when I've started exploring the nether, leaf decay seems to stop and all things stop growing. Tilled earth won't wet, grass won't grow back on dirt blocks. Etc, anything that requires the game to update a block seems to be broken. Any ideas on how to fix this aside from waiting for the next snapshot for it to hopefully be fixed? Any server commands I could use that may help?