Few reasons why SAP Support insists to check the issue in latest patch.
- We understand that Frontend patch cannot be rolled out to thousands of user every quater/month. But we recommend to install only on one test PC with latest patch to test the issue. If confirmed that the issue is solved with patch XX, then we save the time of finding the root cause. We may be able to identify which change solved this issue easily after this comfirmation.
- It is only possible to provide correction based in the latest patch. So even if an error is located on lower patch the solution cannot be provided for that lower patch. eg. if an error is located/found in FrontEnd patch (n-1) and the latest released FrontEnd patch is FrontEnd patch n, then the correction will be provided in FrontEnd patch (n+1).
- Due to the architecture of Frontend patch, correction cannot be done by implementing code-snippets as in case of issue with ABAP server, thus the complete FrontEnd patch needs to be installed. Even if emergency hotfix patch is released, the solution will be a complete update of the frontend patch.
- Generally multiple errors are corrected with each Frontend patch. Only important errors are documented and released to customer via SAPNOTE, but NOT ALL. So it is possible that that the issue you are currently facing is already solved with latest frontend patch.
- Very often, the solution is much easier/faster than locating the root cause. Investing the time to locate the error which is already solved with current patch is not very useful. Thus testing with latest patch is important.
- Installing a new FrontEnd patch on a test PC is neither time consuming nor complicated. It takes less than 20 min. It will save more time that is needed in anaylzing the issue (OSS message processing).