By default, the vlan config will be backed up with the running config. However, the vlan.dat file is opaque data, so RME really can't detect if a change has occurred. It's default behavior is to err on the side of caution, and report a change. However, if you do not want a change record to be generated for vlan.dat, check the "Enable vlan Change Audit Filter" box under RME > Administration > Change Audit > Config Change Filter.