First off, don't use the design master for anything but making
design changes. That means in the minimum replication configuration,
you'll have the DM plus two replicas, one local for editing, one
remote for editing. The DM is synched only for two reasons:

1. to propagate design changes

2. to keep it from expiring (at least once a month or so, depending
on your expiration period; the default is 1000 days).

Now, the second issue is that you should replicate only tables, not
forms/reports, because the latter just doesn't work. The reasons why
are kind of complicated so I won't go into them, but the result of
replicating front objects is usually a corrupted replica set.

One of the symptoms of that kind of corruption is that changes just
stop propagating.

There should be synch errors or conflicts reported to you if you
open the design master or the replica.