As per the compatibility matrix Cisco NAC Agent version 18.104.22.1688 on ISE 1.2 is supported for Windows 8 with IE 10. It means that you are on the supported version only.
For the agent not popping up , can you please check the below settings.
1)In Windows 8, Internet Explorer 10 has two modes: Desktop and Metro. In Metro mode, the ActiveX plugins are restricted. You cannot download the Cisco NAC Agent in Metro mode. You must switch to Desktop mode, ensure ActiveX controls are enabled, and then launch Internet Explorer to download the Cisco NAC Agent. (If users are still not able to download Cisco NAC agent, check and enable "compatibility mode.")
2)When you create a Cisco ISE client provisioning policy to accommodate Windows 8, you must specify the "Windows All" operating system option.
182.ActiveX is supported only on the 32-bit versions of Internet Explorer .
183.Java version 1.5 is the minimum version required for Java Applet support.
184.Testing on international languages has been verified with ActiveX. Although Cisco believes the installer runs successfully in the foreign language with Java, this has not been verified. In the event of a Java installer issue, Cisco NAC Agent installation on international language operating systems defaults to English.
185.Web login is not supported on 64-bit versions of Internet Explorer.
186.The temporal Cisco NAC Web Agent can be launched from the Web Login Facilitator using ActiveX from the Internet Explorer versions or via Java applet from the web browsers listed as supported for Windows systems.
187.You cannot install the Cisco NAC Agent or Web Agent using Metro Mode in Internet Explorer 10.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...