Wow, some kind of answer. HOW does it determine it is not required???? Where is WUA getting the information to say it is not required?
WUA gets its information directly on/from the local computer.
"required" for a deployment, is the alternative to "available".
The difference, is basically "mandatory" vs "optional".
This is totally unrelated to an update being "not applicable"/"not required".
For Software Updates Management in ConfigMgr, the WindowsUpdateAgent (WUA) performs a scan/detect against the SUP/WSUS in your ConfigMgr hierarchy. This scan/detect, compares "what's on the computer" vs "what updates are available from WSUS".
The result, is a list of updates, which is then examined for "is already installed", "is not applicable", "is applicable *AND* is not currently installed".
If an update is determined to be "is applicable *AND* is not currently installed", then ConfigMgr will go on to determine if there is a deployment for that update in your hierarchy, has the content been acquired from MSFT etc. It will then check
for the deployment type (available/optional vs required/mandatory) and check for deadlines you've set etc.
None of that happens if an particular update is assessed as "not applicable /or/ already installed", because, there is no action possible/necessary if the scan/detect outcome for that update is "not applicable /or/ already installed".
One of the common reasons why an IE upgrade won't deploy via SUM/WSUS, is missing pre-requisite updates.
IE10 has quite a few pre-requisites (as does IE11), and, the necessary pre-requisites were changed at some point by MSFT *after* IE10 was released. (from memory, an additional update was added to the pre-requisites list.
So, your previous setup probably worked fine, but then, MSFT added an additional update to the pre-req's list, and you are missing that one.
Check in these forums for related discussions, there have been quite a few. There are also MSFT KB articles which describe the necessary pre-req's.