I recently, July thru August 2016, experienced this SMB scan to dfs issue, at a large national client with multiple locations. The issue was only at the clients HQ location, and didn't occur at remote locations located in plants. They were running a mix of WC7830-35-45-55's and 1 WC7970. After much troubleshooting, it was determined that the issue was only at their HQ location which we later confirmed was utilizing Dfs. We only pinned down the issue after crearing a Xerox Log on the issue, and multiple trace files that were sent to Xerox 2nd level, and ultimately to 3rd level support.
It also took a lot of attention and focus by the Xerox TSS (Technical Support Specialist) and other sales folks within the Channels group as this was a large multi unit install. Curiously enought the WC7530's at the customer had no issue scann to the same dfs file system????
The current firmware at the time AUG-11, sepecific to the WC7830 was SPAR (073.010.116.19700) and equivalent versions on the 7845-55 and WC7970's. After analyizing our network traces, 3rd level support sent a Patch ((950888v1) that "specifically" addressed the SMB scan to Dfs issue only!
We recently 11-14-2016, added a new WC7830 with the current (Oct-14-2016) SPAR firmware 073.010.126.28110 and again was unable to SMB scan to dfs, thus confirming that the patch was not included in the most recent firmware release. We had to rollback the wc7830, using Altboot, to 073.010.116.19700 AND reapply the 950888v1 patch to get SMB scan to dfs working.
PS were were unable to apply the 950888v1 patch to the current Oct-14 Firmware 073.010.126.28110
Our hope is that eventually this patch will be included in future firware updates, until then proceed with caution, and hope this info is useful