When you delete a docment manually on the Enterprise Edition 5.0.1 build 5003 bucket，but this docment won't be synced to android client!

Mobile
4

If you remove or delete a document via SDK or directly couchbase server, the oldDoc will be null. You don’t have to do anything specific in terms of putting deleted documents into channel - the SGW will take care of it for you. The document is already in a channel and would now be updated with the _deleted flag as true.
This test would be the check to see if document is removed.

  function isRemoved() {
    return( isDelete() && oldDoc == null);
  }

So this is all you would have to do in your sync function …for example

function sync(doc, oldDoc) {
  /* sanity check */
  // check if document was removed from server or via SDK
  // In this case, just return
  if (isRemoved()) {
    return;
  }

// rest of your sync function ...