The path that I would take before opening a case :
- Read the release notes and understand what is modified in the new release (if any of the features that I'm using are modified I will check those first - enable debug and try to see if anything presents an error)
- Read the known issues - this could advise you on what to expect as not working and never upgrade in the first place.
- I wouldn't recommend upgrading in production to an early deployment unless the FIXES that it brings addresses something that I'm experiencing. - This is more of an advice.
If that doesn't provide any solution next step would be open a case and at least you have a lot of leg work saved for the Aruba tech and possibly closer to the solution.
I was able to find multiple reasons why the issue would be possible to occur on you controller only by reading the Known issues and limitations portion of the release notes of 6.3.1.2