Why do some patches have multiple entries in the approval list?
You might see a patch such as "Windows XP Service Pack 3" listed several times in the patch approval list.
As you may or may not know, Microsoft updates the Microsoft Update Catalog for various reasons and this is why we see multiple updates for the same update having different unique identifiers and publish dates. They sometimes also have different download links and/or installation binaries.
When ever a patch scan is run on a specific machine, the scan results provide the 4-part unique identifier for each update. This results in a specific record in the kaseya database. Kaseya uses the unique identifier provided in the machine's scan results to associate this particular update to that machine.
So, even though the patch policy shows apparent duplicate updates for the same KB, it only means that for each reported update that there was at least one machine that reported that update. It does not mean that all machines will see all of these updates. Each machine will only see the one version of that update that was reported as part of that machine's scan.
As for what is the differences among the multiple updates, it is impossible to know. Microsoft updates the Microsoft Update Catalog for many different reasons. Sometimes, it is just a catalog data update and the binary is not changed. Sometimes, the binary is changed to fix an installer-based bug that had no effect on the actual patch contents.
If Microsoft has to re-release an update because of a problem within the actual patch, they typically release a new binary with a version number in the file name. If it does not require a reinstall, the detection logic does not change, so the update will not be reoffered as missing on the machine. If the nature of the update change does require the update to be reinstalled, the detection logic will be changed and it will be reported as missing again even though it was previously installed. Of course, this will show up as another separate update in the patch approval page even though the KB number has not changed.
The good news is that each specific update is mapped to each machine using the update's unique identifier, so each machine will only have one of the apparent duplicates associated with it. Since Microsoft controls the detection logic in the Microsoft Update Catalog, updates that must be reinstalled will automatically be reported as missing and can be treated like all other updates.