Internal server error when accessing "Groups" tab in "Activation Keys"

SUSE Manager Server 5.0.3

Adding a "system group" (System Groups) to an "activation key" results in an "Internal Server Error"
The following error is displayed on the SUSE Manager - Activation Keys - Groups WebUI page:

Internal Server Error 
The server experienced a problem which prevented your request from being filled out. It may not be possible to execute this action at this time. 

Please help us correct this problem by contacting us with details of how you received this message.

The error in the rhn_web_ui.log shows a java.servlet Exception:

2025-03-17 14:05:10,404 [ajp-nio-0:0:0:0:0:0:0:1-8009-exec-5] ERROR com.redhat.rhn.frontend.servlets.SessionFilter - Error during transaction. Rolling back
javax.servlet.ServletException: javax.servlet.jsp.JspException: java.lang.UnsupportedOperationException.
...
Caused by: java.lang.UnsupportedOperationException
...
 at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:155) ~[taglibs-standard-impl.jar:1.2.5]
  at org.apache.jsp.WEB_002dINF.pages.activationkeys.groups.list_jsp._jspx_meth_c_005fimport_005f0(Unknown Source) ~[classes/:?]

Even though there's an error in the WebUI, listing the group works on the command line. The group is also associated with the Activation Key.

Working with that Activation Key and the Group it's associated with, is also possible. 

A bug has been reported to engineering and a PTF (temporary fix) has been created by engineering.

This is tentatively expected to be fixed in an upcoming patch release.

Steps how this can be reproduced:

1. Create a system group in "System Groups"
2. Create an activation key in "Activation Keys" and navigate to the "Activation Keys" "Groups" tab.
3. Add the group to the key and navigate back to the "Activation Keys" "Groups" tab.
4. The next page will show the "Internal server error".