@ifernandez welcome to the Rockstor community. You listed the Linux Kernel version above, but I assume you are on Rockstor version 4.6.1-0?
Since I am not an AD expert, have you read through this thread below to take a look whether any of your settings are similar/different and whether (despite the fix that was introduced and is available in the latest version) any of the proposed workarounds might work for you?
Maybe @ocelot11 sees this post and can provide some further insights/questions to help you along.