The Abu Dhabi authorities have indicated that they are not accepting supporting documents that are issued in other Emirate for foreign nationals who intend to apply for Dependent Visas. They intend to review each case on their individual circumstance and may even request additional supporting documents or a personal appearance of the sponsor.
For new Dependent Visa applications, all supporting documents must be issued by Abu Dhabi (tenancy agreement, water and electricity bills). For dependent visa renewals the Abu Dhabi authorities can accept supporting documents issued in other emirates, but once the policy has been fully implemented they will cease to do so.
This change in policy poses a challenge to those employers that live in Dubai, but work in Abu Dhabi. There is a high chance that the Abu Dhabi authorities will either ask for more documentation or reject the application outright.