Hello Derek,
Yes, a member of the engineering team just restarted the Sandbox
servers, and things do appear to be functional.
This behavior does appear to be tightly coupled with the Sandbox DB
refreshes. The issue, though, is that the refresh took place late last
Friday (as previously announced), and this behavior didn't crop up
until Tuesday morning. It's that discrepancy in timing that makes it
difficult to determine what the underlying problem is, and why it take
days to manifest itself.
In any case, please let us know if anyone sees any additional issues.
Cheers,
-Jeff Posnick, AdWords API Team