We've got an environment where we've got about 40 remote locations, and based upon their needs, we'll provide a read-only DC (if they have a small number of employees and don't host any applications) or a read-write DC (if they're a large office and/or host application servers that use AD authentication).
We've had strange issues where some of the offices with RODC's will lose their internet connection, and everyone in the office is unable to authenticate to anything at all locally until the connection is restored. We thought that we were perhaps making the classic mistake of only allowing user accounts to be cached on the RODC, but we've verified that computer accounts are as well (basically, Domain Users and Domain Computers). We put a RWDC in the same location, and the next time they lose their internet connection they're just fine.
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