Row not being deleted from the publication when it's deleted in a subscription

We've merge replication configured in our environment(1 Publisher, 3 Subscribers) and We know by default merge replication is bi-directional. Its working fine in case of inserts i.e, if a row is inserted at publisher then it's getting updated at subscriber and vice versa. The real issue is, if row gets deleted at publisher then its getting deleted at subscriber but, if a row gets deleted in any of 3 subscribers then its not getting deleted at publisher. When a row is deleted at publisher then it's getting updated in MSmerge_tombstone(Publisher). But, in case of subscriber, the corresponding row(rowguid) is not getting updated in MSmerge_tombstone(Subscriber). I think that might be the issue, even merge delete trigger exist on these tables(Subscriber). Please help me out, as it is a production issue. **Note: delete_tracking is enabled(set to '1')** Publisher(2008R2 sp1-Enterprise), Subscribers(2008R2 sp1-Standard)